Some research down the same route bounced the gt2256v as the turbo to use, it seems to be the same one or similar that allards sell as a kit, the quest is finding one which is pressure controlled, most seem to be electronic, especially looking at doner vehicles.
The ideal doner is an iveco van it seems, as it has the 4 bolt pattern at the manifold mount, the exhaust is another story, it will need to be rebuilt to suit.
G