Is "IMAX GT Laser" the ones to look for? Looks like Cineworld Leicester Square has the best setup around SE England.
Hmm... That list doesn't include my local - Cineworld Broughton, which I went to from the second day it was open until the plague times. It's not a laser one though.
Looks like that list is quite out of date - it doesn't include the Odeon IMAX in Cardiff either. EDIT: Actually looks like it's waaay out of of date. Like green milk out of date. According to the IMAX website, there's about 50 IMAX cinemas in the UK, compared to the list of 17 on the wiki page.