2014 Bentley Continental GT AC not cold enough – any specialist recommendations in Sharjah?

I bought a used 2014 Bentley Continental GT about a year ago and it's been a dream, except for one thing. The AC just doesn't seem to get as cold as it should, especially when the outside temperature goes above 40 degrees. On a normal day it's fine, but on really hot afternoons it struggles to keep the cabin comfortable. I took it to the dealer in Dubai and they did a quick check, said the refrigerant level was fine, but quoted me 3,500 dirhams just to do a full diagnostic which they said could take a full day. That seems crazy to me. I've been searching online and found a page with more information about a shop in Sharjah that specializes in luxury European cars including Bentley. Has anyone here used an independent AC specialist in Sharjah for a Bentley or Rolls Royce? I'm nervous about taking such a car to a random shop, but the dealer prices are just insane. I'm wondering if the issue could be something simple like a clogged expansion valve or a weak blower motor, or if it might be a more complex issue with the climate control module. The car has about 70k kilometers on it and otherwise runs perfectly. If you've had AC work done on a Bentley in the UAE, especially in Sharjah, I'd love to hear about your experience. I just want the car to be ice cold like it should be. Thanks in advance.