I think you chaps just helped figure the leak . the car is booked for inspection 2 at 60000 miles and annual MOT inspection so i shall ask tech to look at a/c compressor .
i have removed the stiffener plate to try to eyeball or feel for leak with no specific sign of the actual leak point . i even looked around from above at a later time with an endoscope and can only determine the leak as coming from that area , can`t even get the scope right in there without pulling a few bits . car has bmw extended warranty thankfully .