To my mind if some X5s don't do it and some do, it is not a case of adding rubber blocks from the bottom of chairs or sticking tape on things! Something is obviously wrong and I wanted it to be right not bodge it.
Sure enough after adjusting the stoppers, tightening up the latches and generally having a good look eventually I found one of the two tiny plastic caps on the rubber blocks of the central boot striker missing.
It had obviously somehow been knocked off or was never there and as it "clamps" the latch, was an obvious culprit.
So £12 later for a complete new striker from BMW (can't buy just the cap of course


Jay