Well, back off holiday on Monday, arrived home late, after loaning a Discovery from a friend for a few weeks.
Went to Audi,
they've replaced the compressor and the accumulator, apparently the accumulator has a valve in the neck that was faulty.
they haven't charged for the accumulator or additional labour, but the bill stood at £2.4k, including a tyre they found a bleb on.
after lots of moaning, shouting, arguing, got the bill reduced to £2k, paid & left.
i'll put that one down to experience, and hope she runs well for the next few years.
it's lovely getting out of a discovery and back in the A8 i must say