Yes, I've used Cousins fairly often over the years.
Good service, good quality and reasonable prices. There are lots of small items that are very useful for the modeller that are often hard to find elsewhere. They will sell you anything in their catalogue but of course the better prices are when you buy in volume (which I normally don't) and you also pay a small postage charge. If there is something inexpensive I need (£2-£3), I will also tend to have a look for other things that might be useful or where my stock is getting low.
Rather like allowing my wife in the Supermarket (than just using Click & Collect) this does cost a bit more but not excessively so (and normally much less than my wife's impulse buys) 
Regards,
IanT