You kinda answered your own question the Cosworth would be same as any other MK1 seen as that is what it is based on, at a guess I would even say MK2 are the same, and the wipers defo need to be working to pass an MOT.

Round here there are loads of them in scrappys.

Don't think Mondeo ones will fit as the wiper arm would be longer this is due to modern cars having much more depth in the screen (Top to bottom) Escorts would be smaller I would think.

Martin