I've now got to the bottom of this. Spoke to many retailers including Pelican, ForestFine and of course MM. There has apparently been a quality issue with this part in that the bond between the 3 strips of rubber seal (i.e. top of window bit and the 2 bits that go down the sides) has been known to fail. This is exactly what happened to mine and is why MM have no problem replacing the part. The problem is that no-one has this part in stock

MM, Pelican and FF all are out of stock. MM said they've had it on back order for 3 months and don't expect anything till possibly July (which you know will be September). Now I have a car ready for the summer but no main windscreen to roof seal, so I can't put the roof on

. I asked MM to at least send my broken seal back so I can at least install the roof, but they said they've already sent it back to the manufacturer.
Has anyone got a decent secondhand one I can borrow until MM send me the replacement new one at the end of the summer? Pppleeeaase
