No problem.
The number is Ford 1333905 and I bought it from here:
https://www.ebay.co.uk/p/Ford-1333905-A ... 2126289649That sounds like exactly the same issue I had. I literally had to hammer the first one in and even then, it would pop out when you unplugged something. If you compare them at first they look the same but they are slightly different lengths and thickness.
EDIT: I've just realised this is the same one you bought! I must have bought this after reading your post. Mine went straight in though with a satisfying "click". I didn't have to do any modification to the frame. I think if I can remember correctly though, I removed the plastic bit and fitted it first, then fitted the metal parts (I think).