So she failed MOT on this too. Was gotta attach to last post but forgot The 6 bolts holding the flange on, cannot for the love of money get them to shift. I have the right tool but rung 3 of them now, ratchet, rattle gun, a little heat etc... will not budge. Cut old gaiter off. A bit unprofessional but... Has anyone cable tied a gaiter to the outside of the flange and it worked?. Not much room but I'm struggling here to get the bolts undone.
Make sure the insides of the capscrews are clean so your tool fits nice and tight ,fit the tool into each one and hammer the end of the socket extension with a decent hammer several times ,if the screws are chewed out the next step is use a pair of vicegrips just make sure the jaws aren't worn out because the need to bite into the heads . Used both methods many times to good success ,you mentioned you have used some heat which is good but you may need to do it several times , I wish you good luck but take your time as your only other option is to drill the heads off ...not fun. Cheers.