My old Audiolab 8000a was bought in 1987 and has never had any work done to it. I am considering having it “serviced” and having the capacitors replaced at the same time to perhaps delay me blowing a fair amount on a new amp. The MM/MC phono stage is all upgraded at the same time and the whole job comes in well under £200 which seems very reasonable to me. There are no real problems with the amp apart from a perceived looseness in the bass which may just be my familiarity with the amp and a crackling from the volume control if you turn it before it’s fully fired up. So, is this pouring good money after bad or worth it?
I really like the amp as it is a truly integrated amp in as much as it has everything in one box unlike many modern amps which omit vital facilities such as a phono stage or even headphone socket!

Do the upgrade. As an owner of a 1985 Cyrus 2 which has been re-capped, I can vouch that nothing newer for less than £750 will come close.

I’d be intrigued to know what the “service” entails exactly (apart from swapping the caps)

I think most of the work is in the cap replacement but I believe all the circuits are checked for DC leakage, bias checked etc. Some of the MC phono upgrade parts are a bit more expensive than standard and the combined MM/MC upgrade is a bit more involved than a single MM upgrade. The chap who is going to do it specialises in Audiolab/Tag equipment and has a very good reputation on audio forums for his work.
The pre/power section is also split so it can be used as a pre-amp only, a recognised audiolab procedure. I know very little about electronics so take his word on trust.