For the last few years i have used
etyres.
Good prices, and they come to you as part of the service - which is normally a significant charge if you use some of the major well known companies.
Subsequent punctures are fixed for free (and i have had a couple - so that's another few tens of notes saved)

BlackCircles (who i have also used) were a pennies cheaper that etyres, but you have to wait for delivery and then attend the nearest premises to get them fitted.
I am also in Midlandcestershire, so hopefully you will get a similar good (franchise) service.
mb