Hi Simon
If like me, you are fitting an early 1.8 Zetec ( Mines a 1992 Silver Top )
You will need a Mk 1 Mondeo 1.6/1.8 clutch & then you will have to source a clutch release bearing .... Quninton Hazel part no: CCT133
Here's a link to the sort of kit that should be suitable
Mondeo Mk1 clutch
I'll have a look in the QH guide for you in a while .... Just to check the spine size is suitable .... Don't jump in & buy one just yet
Of course I am assuming that you are using the type 9 gearbox
The standard 1.8 flywheel should be fine as is.
You will need to fit a spigot bearing into the Zetecs crankshaft at the flywheel end ( Easy to order from ford or ebay, exactly the same as the original Sierra one )
Mine is all fitted up & looks like it will work a treat