I've mainly had free sites with ads on,but the good thing about them is you can try them out and get your site up and running and then get your domain and upgrade to an ad free site.
freewebs and bravenet are both quite user friendly,but they are both American so they might not support .uk domains.
In my experience UK based hosts don't give you the totally free option,although I could be completely wrong.
I hosted my site here http://www.xnynz.com/ .
Here i got the web hosting service at cheap price..Not only this, it also provides the domain registration service..If you need, visit the site..