Good luck with the search. I'm in South Wales and tried to find some last year. You may need to travel a bit to get some, all the places that had them around here seemed to be in Carmarthen.
I eventually got a hen and cockerel at 12 weeks old from someone (found out purely by accident) that had hatched some RIR eggs they bought.
They are lovely cheeky birds, I hope to try and hatch some eggs from them in the summer.