Coincidentally I was reading up about BMW aircon as I just had my Plus Four system regassed. It had failed when tried during the recent hot weather.
On my other cars I always used it at least once a month to keep it checked. I haven't done that in the Plus Four. My error! The car was in MMC for a job two weeks ago and they regassed it while it was there. It works properly now. I'll definitely use it monthly from now on. It just needed a regassing, no other issues......yet! Hopefully no seals damaged or slow leaks. A proper regas involves leak tests anyway so if none found it should be ok. 🤞
It's basically like your fridge/freezer. These run continuously so tend not to suffer non-use problems with compressor, condensor, seals.
A good aircon servicer will do checks for leaks, compressor etc and refill gas.
From your photo the condensor and pipes are seriously at risk being so low and exposed. That needs sorting. Can you raise the condensor "rad"? Turn the pipe connectors 90 ( or more)? Fit a plate to protect but not block off airflow to the condensor ?
From my investigations ( google and you tube) components should be easy to find but access might be awkward, especially for the compressor pump.
