I would prefer it if you gave a shop name rather than just 'most hardware stores'
B+Q Jewsons Homebase Focus ...of course it depends what form of CPVC you're looking for..
I worked for Saint-Gobain Building Distribution Ltd - the brand is Jewson, singular. L
(or non-possessive) L
Picky, picky.... I stand corrected. Steve
Sorry, but I spent too long in there... Also Graham, Archibalds, and a load of others... L
If you already know that 'most hardware stores' is a viable answer, then pick up the phone and call a few that are located near where you live.