Venhill are based in Dorking, Surrey. Pass them every other day on my ride. They were the importer for Magura for many, many years from the early Hydrostop days through the Tomac period. They still have a window poster of JT on a Giant today in their warehouse window.
They supplied their own chainrings, titanium bolts and many other things. They used to be a lawnmower, motorbike, go-kart type parts place and are run by some great people.
They helped me out a bunch of times as a teen with bike bits, fairly certain my old man used them for spares for his mower back in the day, and they have been an endless source for things like solderless nipples for graft on brakes and cable pipes for Yeti Stems later in my life