Meguiar's has quite a lot of new distributors in UK now. It's more convenient for you guys to source for detailing products when you stay outside of Central London. I haven't seen many car accessories shops around my place in Paddington. I came across a few shops which only sell Autoglym products. It's such a sad case...
Zaino's claybar is not a bad choice, try to find who is the distributor for Europe countries.