Car is worth IMHO £2200 with a working engine as it's cat d,prob about £2800 as a straight car.blown engine,£1000-1100.I'd say if he's happy with the car it's worth repairing IMHO,as posted if a lumps £700 a home mechanic could easily fit it or as a backstreet garage I wouldnt expect to pay more than about £150 in and out.

Might be worth getting the belt done while out as it's less labour for the mechanic so should save you a few bob.I'd guess,engine in/out,belt/tensioners etc done,plugs,oil,filters,coolant refill,exhaust gasket/paste should come in with parts about £400?

I'm not 100% on that but as long as the parts come in round £120 that's not bad business.