In the past I've got my detailing stuff from Autopia - it's a great site with great products and great service.
The only problem obviously was the shipping charges. So it only really made sense when I was buying lots of stuff and I could never find somewhere in the uk that stocked all the stuff I wanted that Autopia had.
However I found this place the other week: Clean your car .
It seems to stock all the stuff I used to order from Autopia: Sonus, Carlack, P21S, Collinite, poorboys, 303 Aerospace etc etc.
Maybe this is old news to some of you guys but it's news to me. My first order is coming this week.
(PS - nope, I'm not affiliated with the site in any way - just happy to see somewhere where I can get my sonus etc stuff in the uk)