Thanks for the reply, the settings were correct but it was my own fault it was not working.

I just activated shared SSL certificate prior to installing zen cart, so to check SSL was working i had opened the SSL URL (secureserver.co.uk/mywebsite) to my site, but then when i started running the zen installer i was still running it through the SSL url (secureserver.co.uk/mywebsite/cart/) instead of navigating back to my real url to run it (mywebsite.co.uk/cart/) This wasnt a problem until mysql tried to connect which it obviously cant do via the SSL url.

Short answer, stupid me, 1 hour wasted for not realising changing the URL, zen cart now installed and running fine.