I don't know about availability for you guys over the pond,but I'm planning to use one from a MkII Austin Mini.(I suppose you could try ebay)
My original heater core in my AD is shot and I can't find anyone over here to rebuild it.
The Mini one is a small self contained unit and will be more than enough to heat my cab.You can hook up the demist too.
A buddy of mine had one in his '52....it was just the job!
