Ok I have an answer from an experienced friend, When on standard height the bags are rolled over the cylinder and cracking causing leaks but when extended bags are straight and cracks sealed!
Ill change bags and update forum if the case.
Hi, The above is my problem also but the time it takes to drop is shortening - my only question before fitting new bags is why dont the "porus" bags leak in raised mode then?????
Cheers
Martin