Er, Kev's getting old
The ones I use are Flennor, not Dayco. £32 a pair from memory. They work fine, but seem to be slightly more heavily constructed than OEM (Gates) belts. I'm certain the Dayco ones will be fine too, after all, the belts are being changed so often on the racers, that wear & ageing issues are not a factor. Just don't run them too tight.