Richard
Pedanticist is correct - the single most important place to start would be a listing on DMOZ (Open directory). Make sure you read their guidelines before submitting.
As for other UK search engines and directories, this is a frequently-asked question here. This thread:
[webmasterworld.com...]
contains links to three previous discussions with plenty of suggestions for sites to submit to.
One other thing you should do is run your site through the Sim Spider tool to see if search engines can actually index it:
Good luck!
The best site we have been using over the last three years is <snip>.
What we like about it is that its easy to use and fast loading and the best of course is that its free to list a site's url.
Just my two cents worth!
[edited by: engine at 8:27 am (utc) on Jan. 24, 2003]
[edit reason] no urls, thanks. [/edit]