if the bottom end is a zetec it could have only came from a mondeo(which would be early 90's). the only 2.0 escort they did was the RS2000 and the I4 engine looks very different to a zetec. and if i remeber rightly there is only one nut. that goes into the upper body bit near the header tank, nut there. long bolt from inside the drivers side wheel arch (think you have to drop the liner out) and undo the 3 bolts that bolt it to the block. either use a 6 sided socket for the bolts/nuts if they are that tight. or a twist socket designed for shagged nuts and bolts if they are fully funked. a basic set wont cost much 20-30 quid..but ive lost count of the amount of times they have got me out the brown stuff

any zetec engined fiesta rear mount will be fine for you to replace it with

hope that helps
Jam.