Thanks for the replies so far.
AFAIK its the stock down pipe.
Its definitely leaking, the car was regassed months ago and it lost it all by the next day. The a/c bloke used a dye when he re-gassed it. The only point of leaking was the compressor and he showed me with his ultra violet light where the dye had stained.
Is anyone aware of if there are different compressors used by different series of engines?
My car is a 1990, but it has a rev2 engine in it.
The car is at a local a/c specialist, i'd like to persevere with this bloke so i'll take what you all have said so far to him tomorrow when i wake up. (3.20am after shift here now...

)