Check out the YouTube video from South Main Auto:
Horn Doesn't Work... Service 4WD Light On... Let's Diagnose It!
He fixes something that is very easy to fix but brought in my another shop.
Given the compressors age and/or mileage the shaft seal and other seals aren't likely to last much longer anyway. I don't care if you live in the UK and maybe don't use A/C all that much, age is a factor as well. I'd replace the compressor.
How many times has your airbags actually deployed?
I would expect an airbag light or maybe check engine if airbags aren't working.
I made it to old age without air bags.