Hi Nigel,
I have a 1986 Live Axle chassis with an 1800 Zetec fitted. It is mated to the 4 speed Escort sport box rather than the 5 speed. The engine will drop in, but the gearbox needs to be moved back - disconnect the prop shaft from the diff, remove the gearbox maounting bolts and it should slide back about 4 inches. It is just enough to get the engine in. It is also possible with the gearbox mated to the engine and slide them both in togther. I've done both, and can't say which is better - they are both tight and knuckle skinning!
Good luck,
Dave H