Always a chance they could be for a later mini , once the pom's went to the internal door hinges their mini's used taller and wider rear windscreens and taller side rear window's , can you check them against a later model mini (anything with internal door hinges ) ? Other than that no ideas , where did you get them from , a local dealer or did you import yourself ?

Don't cut them , good chance they'll leak , ring the place you got them from and check in case they have a batch that is marked wrong or something . A mate and I drove 4 hours to a Brisbane MG specialist to pick up a windscreen for his MGA , got hom and found it wouldn't fit , 3" too wide . The whole shipment had been cut to an oversized template as somebody stuffed up the zoom factor on the computer , basically there can be problems with things , just check it's the right part number and if they have had any others with problems . How much bigger than the window opening is it ?

I've just replaced these on my wife's mini. Although it is a pom Mk3 with the 'big' windows, I thought that the one piece rubbers were made too big. Same as you - 3 sides on and the 4th seeming way too big. In desparation, I went back to side 1 and adjusted it so I was really squashing it into the corners and compressing it along the sides as much as possible. This worked and the rubber fitted!! It also seems to have a fantastic tight seal now and NO water comes in.