In their day, the size of the Ford Granada MK1/MK2 was mahoosive compared to other vehicles of that era. It was a big comfortable car with a really big boot. My brother in law had a few Granada Ghia X Pack’s and loved them.
Obviously they now seem low and smaller than modern big fat cars but they were big in their day.
Rangie, if when purchased and at a later date you find the auto gearbox randomly changing gear or holding a gear, check the viscous coupling on the radiator cooling fan. The gearbox senses engine load so changes gear accordingly, but it has been known for the coupling to seize, causing engine load and erratic gear changes. Very simple to check, simply lift the bonnet, spin the fan and the fan should free-wheel easily by hand. If it doesn’t spin freely the coupling is seized. Not a big drama but it did catch my brother in law out the first time it happened on one of his.
Good luck with the purchase.