Luckily the units where on a stand which was at just the right hight to lean over and get at it with the pepperpot burner on the oxy kit. Good job it was only leaking on the top where the copper is joined to the steel condenser as it would have been a right pain to get at the underside.
Was in a rush as the milk tanker was waiting outside to pick up the evenings milking, or so i thought. It turned out he parks on site an picks up in the morning but no one thought to tell me
I've seen quite a few of these prestcold/copeland units leak here, always worth a check if you can't find a leak.

Jon