Where can I ride Paris-Roubaix style cobbles in the UK?
In all seriousness the only places I can think of where I've seen cobbles would be town centres. If you do a search on Google Images there are some stories dated 2013 which have images of the cobbled Market Place in Beverley - ironically the story there is that the council wanted to tear them up for health and safety reasons.

I'm pretty sure I once rode through a town in Dorset which had cobbles - I forget exactly where (possibly Wimborne Minster) but again it was a town centre.

Contrast that to what you see in Paris-Roubaix. Those cobbles appear to have once been vast thoroughfares through the countryside - they have got to be Napoleonic in origin, a way of getting his troops from A to B. That story about Beverley dates the cobbles to 175 years, so roughly the same ballpark, so I'm sure if you travelled back in time far enough you'd find such roads in the UK.

I suspect road building policy has a lot to do with it too - France is twice as big as the UK so possibly in France they just decided to build brand new roads from scratch, taking a slightly different route, and to allow the old roads to decay to what we see today. Maybe in the UK they took the approach that, to save space, they dug up the old road and replaced it with new, following the same route.