Hi,
I never get tired of seeing mk1 vans! They aren't too common in my view but they have those classic lines. I think "The originals" thread is right on the look. Mex front arches and that overlapping lip on the back one is the way to go for sure. Buble arches really are for escort cars.
As for the finances, Join the sporting escort owners club (if you haven't already) and they will give your a magazine which is good for spares along with Classic Ford which also has shed loads of tech on escorts. they're a real goldmine!!
I saw a cosworth engine for £1500 recently. Its supprising how cheap you can get things if you exchange budget for time and effort. You can get there if you have cash waiting and are patient enough to be there for that cheap deal.
Good luck with it.