I agree, it's a misery. I drilled a hole in the GRP, directly above the filter bolt which lets me get a socket down there easily to loosen and tighten. Between (extensive) service periods, the hole is taped over. I have taken to double-bagging the entire filter assembly, loosening the top bolt and dropping the whole gubbins into the bag for sorting out somewhere less crampy. So far, no spillage. I have no miracle answer to the tiny wee o-ring though
Ewan
P325/30