Can't say they will be direct fit, but ford do not like designing new parts if there is a suitable old part, the seats from a similar age capri, or cortina may fit, sierra ones may fit too.
Finding seats for those i just suggested might be as hard as finding granada seats, so i think really, for ease of finding, you want something fairly common.
Some newer fords could be worth looking at, mondeos, focus'?
If you are able to cut and weld, you could make nearly any car seat fit, from any car. You could even wire in electric motors, heated seat pads and cooling fans from higher end seats.
I'm thinking about changing the seats in my transit, I believe it is just a case of welding or bolting the new seats to the base and runners.
An added bonus with the Granada, is you have no airbag light to worry about.
Have a look round at your local scrap yard? Most things can be made to fit.