So, did the one click upgrade via my webhost on my WordPress install - http://www.citadel-of-light.com and it worked...kidna.
WP-Cache is making a mess of things. I can still log into my cp and when i go to the WP-Cache link i get this:
Main optionsError: wp-content directory (/hermes/bosweb/web034/b345/ipw.cdescryc/public_html/Blog/wp-content) is not writable by the Web server.
Check its permissions.
Cannot continue... fix previous problems and retry.
Now up until i tried to fix (doh i know) the problem, the first page of the blog gave an error saying it couldn't write to a long URL which ended with Blog/wp-content/cache (no such file exists).
Read a support post about editing the config.php file and remove the "define('WP_CACHE', true); //Added by WP-Cache Manager " part - not a good idea apparently since the site is now 500 erroring.
Don't really need wp-cache, just need to get upgraded and up and running.
Thanks in advance for your help.