Buzzing Air con compressor (video)

Hi, I have the following:

2014 Forrester XT
26,000 miles
Serviced at local Subaru dealer since new

Today I noticed a weird buzzing noise in the engine bay, on further inspection it looks to be the air con compressor (see video). I've noticed recently when the air con kicks in I can hear a sucking sound as if it needs a top-up and it's not as efficient as it should be (which is has never had).

1. Does it seem like my compressor is now screwed?
2. Would a top-up maybe fix this?
3. Are they serviceable or just not worth it?

I have a Honda S2000 and the specialist who looks after it is very well regarded so am thinking of taking it to them. Usually they are happy for people to bring their own parts or source them which is handy. If I need a replacement or part where is the best place to get one from?

I can't get a slot in the garage for a few weeks and as my MOT and service is due at the end of November I was thinking of getting it all done then, I assume no real damage will be done in the interim? I guess if it's annoying I can just turn the air con off for now?

Thanks in advance for any help.

Video of problem