The general advice on this (and other) NGs when someone asks for a supplier of a tool or component is 'Google is your friend'.
True, but this does impose a filter on the real world where a lot of smaller suppliers just disappear from view.
I was looking for some plastic channel to go round my new wooden fascia and although I located a national supplier (who only supplied in bulk) I didn't find anywhere local.
Whilst visiting ScrewFix Direct and Ipswich Plastics (who didn't do any UV stabilised stuff) I noticed a small unit with the door rolled up and a lot of white plastic on display. Stopped for a chat, and found that there was a supplier of plastic bits just round the corner. They had a good stock of the bits that I wanted, and would also have delivered for free if I was prepared to wait a couple of days, as I was on part of their regular delivery route.
So a short wander around an industrial estate can turn up all sorts of useful items. :-)
Cheers
Dave R