Add coupon page loading really slowly

The add coupon page has began loading really slowly. Any ideas of what I can do?

### WordPress Environment ###

WC Version: 3.3.5
Log Directory Writable: ✔
WP Version: 4.9.5
WP Multisite: –
WP Memory Limit: 256 MB
WP Debug Mode: –
WP Cron: ✔
Language: en_GB

### Server Environment ###

Server Info: Apache
PHP Version: 7.0.29
PHP Post Max Size: 128 MB
PHP Time Limit: 60
PHP Max Input Vars: 2500
cURL Version: 7.19.7
NSS/3.27.1

SUHOSIN Installed: –
Max Upload Size: 128 MB
Default Timezone is UTC: ✔
fsockopen/cURL: ✔
SoapClient: ✔
DOMDocument: ✔
GZip: ✔
Multibyte String: ✔
Remote Post: ✔
Remote Get: ✔

### Database ###

WC Database Version: 3.3.5
WC Database Prefix: jciw_
MaxMind GeoIP Database: ✔
Total Database Size: 35.73MB
Database Data Size: 24.21MB
Database Index Size: 11.52MB
jciw_woocommerce_sessions: Data: 0.22MB + Index: 0.01MB
jciw_woocommerce_api_keys: Data: 0.00MB + Index: 0.00MB
jciw_woocommerce_attribute_taxonomies: Data: 0.00MB + Index: 0.00MB
jciw_woocommerce_downloadable_product_permissions: Data: 0.00MB + Index: 0.00MB
jciw_woocommerce_order_items: Data: 0.00MB + Index: 0.01MB
jciw_woocommerce_order_itemmeta: Data: 0.04MB + Index: 0.03MB
jciw_woocommerce_tax_rates: Data: 0.00MB + Index: 0.00MB
jciw_woocommerce_tax_rate_locations: Data: 0.00MB + Index: 0.00MB
jciw_woocommerce_shipping_zones: Data: 0.00MB + Index: 0.00MB
jciw_woocommerce_shipping_zone_locations: Data: 0.00MB + Index: 0.01MB
jciw_woocommerce_shipping_zone_methods: Data: 0.00MB + Index: 0.00MB
jciw_woocommerce_payment_tokens: Data: 0.00MB + Index: 0.00MB
jciw_woocommerce_payment_tokenmeta: Data: 0.00MB + Index: 0.00MB
jciw_woocommerce_log: Data: 0.00MB + Index: 0.00MB
jciw_a3_exclude_email_subject: Data: 0.00MB + Index: 0.00MB
jciw_allowphp_functions: Data: 0.00MB + Index: 0.00MB
jciw_commentmeta: Data: 0.02MB + Index: 0.03MB
jciw_comments: Data: 0.23MB + Index: 0.09MB
jciw_download_log: Data: 0.02MB + Index: 0.02MB
jciw_edd_customermeta: Data: 0.00MB + Index: 0.00MB
jciw_edd_customers: Data: 0.00MB + Index: 0.00MB
jciw_links: Data: 0.02MB + Index: 0.02MB
jciw_login_redirects: Data: 0.02MB + Index: 0.02MB
jciw_modalsimple: Data: 0.00MB + Index: 0.00MB
jciw_options: Data: 4.38MB + Index: 0.08MB
jciw_phppc_functions: Data: 0.00MB + Index: 0.00MB
jciw_pmxe_exports: Data: 0.00MB + Index: 0.00MB
jciw_pmxe_posts: Data: 0.00MB + Index: 0.00MB
jciw_pmxe_templates: Data: 0.00MB + Index: 0.00MB
jciw_pmxi_files: Data: 0.02MB + Index: 0.00MB
jciw_pmxi_history: Data: 0.11MB + Index: 0.00MB
jciw_pmxi_imports: Data: 0.06MB + Index: 0.00MB
jciw_pmxi_posts: Data: 0.02MB + Index: 0.00MB
jciw_pmxi_templates: Data: 0.03MB + Index: 0.00MB
jciw_postmeta: Data: 2.52MB + Index: 3.03MB
jciw_posts: Data: 5.50MB + Index: 0.50MB
jciw_post_views: Data: 0.06MB + Index: 0.11MB
jciw_redirection_404: Data: 0.24MB + Index: 0.12MB
jciw_redirection_groups: Data: 0.00MB + Index: 0.00MB
jciw_redirection_items: Data: 0.01MB + Index: 0.02MB
jciw_redirection_logs: Data: 0.01MB + Index: 0.01MB
jciw_rg_form: Data: 0.02MB + Index: 0.00MB
jciw_rg_form_meta: Data: 0.06MB + Index: 0.00MB
jciw_rg_form_view: Data: 0.06MB + Index: 0.03MB
jciw_rg_incomplete_submissions: Data: 0.02MB + Index: 0.02MB
jciw_rg_lead: Data: 0.17MB + Index: 0.03MB
jciw_rg_lead_detail: Data: 0.17MB + Index: 0.41MB
jciw_rg_lead_detail_long: Data: 0.02MB + Index: 0.00MB
jciw_rg_lead_meta: Data: 0.02MB + Index: 0.05MB
jciw_rg_lead_notes: Data: 0.02MB + Index: 0.03MB
jciw_swp_cf: Data: 0.20MB + Index: 0.17MB
jciw_swp_index: Data: 2.17MB + Index: 1.69MB
jciw_swp_log: Data: 0.05MB + Index: 0.06MB
jciw_swp_tax: Data: 0.02MB + Index: 0.03MB
jciw_swp_terms: Data: 0.48MB + Index: 0.76MB
jciw_termmeta: Data: 0.02MB + Index: 0.03MB
jciw_terms: Data: 0.02MB + Index: 0.03MB
jciw_term_relationships: Data: 0.05MB + Index: 0.02MB
jciw_term_taxonomy: Data: 0.02MB + Index: 0.03MB
jciw_usermeta: Data: 2.52MB + Index: 3.03MB
jciw_users: Data: 0.11MB + Index: 0.08MB
jciw_vswpp_votes_done: Data: 0.00MB + Index: 0.00MB
jciw_wc_download_log: Data: 0.02MB + Index: 0.03MB
jciw_wc_webhooks: Data: 0.02MB + Index: 0.02MB
jciw_wfBadLeechers: Data: 0.00MB + Index: 0.00MB
jciw_wfBlockedCommentLog: Data: 0.02MB + Index: 0.00MB
jciw_wfBlockedIPLog: Data: 0.00MB + Index: 0.00MB
jciw_wfBlocks: Data: 0.00MB + Index: 0.00MB
jciw_wfBlocks7: Data: 0.02MB + Index: 0.05MB
jciw_wfBlocksAdv: Data: 0.00MB + Index: 0.00MB
jciw_wfConfig: Data: 0.37MB + Index: 0.01MB
jciw_wfCrawlers: Data: 0.00MB + Index: 0.00MB
jciw_wfFileChanges: Data: 0.02MB + Index: 0.00MB
jciw_wfFileMods: Data: 2.21MB + Index: 0.34MB
jciw_wfHits: Data: 0.42MB + Index: 0.13MB
jciw_wfHoover: Data: 0.00MB + Index: 0.00MB
jciw_wfIssues: Data: 0.00MB + Index: 0.01MB
jciw_wfKnownFileList: Data: 1.09MB + Index: 0.15MB
jciw_wfLeechers: Data: 0.03MB + Index: 0.03MB
jciw_wfLockedOut: Data: 0.00MB + Index: 0.00MB
jciw_wfLocs: Data: 0.00MB + Index: 0.00MB
jciw_wfLogins: Data: 0.08MB + Index: 0.02MB
jciw_wfNet404s: Data: 0.00MB + Index: 0.00MB
jciw_wfNotifications: Data: 0.02MB + Index: 0.00MB
jciw_wfPendingIssues: Data: 0.02MB + Index: 0.06MB
jciw_wfReverseCache: Data: 0.00MB + Index: 0.00MB
jciw_wfScanners: Data: 0.00MB + Index: 0.01MB
jciw_wfSNIPCache: Data: 0.00MB + Index: 0.00MB
jciw_wfStatus: Data: 0.08MB + Index: 0.03MB
jciw_wfThrottleLog: Data: 0.00MB + Index: 0.00MB
jciw_wfVulnScanners: Data: 0.00MB + Index: 0.00MB
jciw_yoast_seo_links: Data: 0.04MB + Index: 0.01MB
jciw_yoast_seo_meta: Data: 0.00MB + Index: 0.01MB

### Post Type Counts ###

acf-field: 62
acf-field-group: 11
amn_mi-lite: 1
attachment: 730
bnfw_notification: 1
jetpack_migration: 2
job_listings: 21
knowledgebase: 16
nav_menu_item: 93
oembed_cache: 4
page: 121
post: 140
product: 31
product_variation: 36
revision: 739
shop_coupon: 43
shop_order: 35
shop_order_refund: 2
sssg_documents: 1
stem: 9
ticket-meta-fieldset: 11
tribe_events: 196
tribe_organizer: 11
tribe_rsvp_tickets: 3
tribe_venue: 51
tribe_wooticket: 21
vc_grid_item: 2
vc_settings_preset: 4
vspplugin_vote: 1

### Security ###

Secure connection (HTTPS): ✔
Hide errors from visitors: ✔

### Active Plugins (25) ###

Better Notifications for WordPress: by Made with Fuel – 1.6.13
ManageWP - Worker: by ManageWP – 4.5.0
Gravity Forms: by rocketgenius – 2.2.6
Advanced Custom Fields PRO: by Elliot Condon – 5.6.10
Antispam Bee: by pluginkollektiv – 2.7.1
BE Subpages Widget: by Bill Erickson – 1.7
Event Tickets Plus: by Modern Tribe
Inc. – 4.7.1

Event Tickets: by Modern Tribe
Inc. – 4.7.1

Google Analytics for WordPress by MonsterInsights: by MonsterInsights – 7.0.5
WPBakery Page Builder: by Michael M - WPBakery.com – 5.4.7
Members: by Justin Tadlock – 2.0.2
Modal Window: by Wow-Company – 3.2.1
PDF Image Generator: by Mizuho Ogino – 1.5.6
Peter's Login Redirect: by Peter Keung – 2.9.1
Post Views Counter: by dFactory – 1.2.11
Redirection: by John Godley – 3.2
SearchWP: by SearchWP
LLC – 2.9.12

ShiftNav Pro - Responsive Mobile Menu: by Chris Mavricos
SevenSpark – 1.6.2.1

The Events Calendar: by Modern Tribe
Inc. – 4.6.13

Vote Up Down WP Plugin: by Maxdp – 1.0
WooCommerce Royal Mail: by Automattic – 2.5.5 – 2.5.8 is available – Not tested with the active version of WooCommerce
WooCommerce: by Automattic – 3.3.5
WordApp - WordPress to Mobile App plugin for WooCommerce & BuddyPress: by App-Developers.biz – 2.0.3 – Not tested with the active version of WooCommerce
Wordfence Security: by Wordfence – 7.1.2
Yoast SEO: by Team Yoast – 7.2

### Settings ###

API Enabled: ✔
Force SSL: –
Currency: GBP (£)
Currency Position: left
Thousand Separator: ,
Decimal Separator: .
Number of Decimals: 2
Taxonomies: Product Types: external (external)
grouped (grouped)
simple (simple)
variable (variable)

Taxonomies: Product Visibility: exclude-from-catalog (exclude-from-catalog)
exclude-from-search (exclude-from-search)
featured (featured)
outofstock (outofstock)
rated-1 (rated-1)
rated-2 (rated-2)
rated-3 (rated-3)
rated-4 (rated-4)
rated-5 (rated-5)

The page I need help with: [log in to see the link]