The issue is now sorted.
Thanks to all out there for your advice and assistance.
I do not understand “..database using phpmyadmin..” I am not technically qualified to use this.
Are you able to help me sort this issue via a freelancer site and I will pay you for your work?
Alternatively, do you have any other suggestions? I am now concerned that others may be controlling my website.
I am running the site; at least, I thought I was until this issue arose. I can still login as “admin” and make changes to, eg. pages, products, etc. I am able to change the password and have done this, so I am the only one currently with access to the dashboard, but I do not have the menu links mentioned above. Any ideas on how to get these links active again?