if kwik fart have ever done a repair job succesfully, its likely because there was so little wrong in the first place!
they aren't even that good at their core business, tyres and exhausts, so their diversity into other area's of mechanical and system repair should be taken with a huge swerve in my opinion.
however, on the exact subject of air con regass, many of the so called "specialists" arent exactly brill either.
a lot of people have simply bought the now quite cheap recoup and regas machines, got themselves a bottle of r134a, and call themselves an climate engineer or similarly fab title.
me personally, i'd get on to ebay.com (usa) or ebay uk but include worldwide searches, and get yourself a pressure valve and regas kit.
ive had one for many many years from the states, where air con is not still the hocus pocus dark art black magic it appears to be here in the uk.
it comes with a multitude of adapters, from japanese and american to european common fitments, a simple pressure gauge, and the boss adapter that fits to and pierces the top up cannisters.
get yourself a few cannisters of pre-mixed top up, that include a mixture of gas, lube oil, seal protector and leak indicator, and hey presto you'll be as well versed as any kwik fit expert!
ive done literally loads and loads of cars with a simple top up and pressure test, and salvaged hundreds of pounds in the process.
essentially, if you have gas in the system, up to the required pressure, and the compressor clutch still fails to throw in and circulate the good stuff, you have another issue, but you won't have spent an arm and a leg just to have some numskull tell you
"it dunny work mate", "Gis £40"
DIY first for me every time, so called experts as last resort, but Kwik Twit, never ever ever ever never!!!!!
thats my two penneth