Thanks everyone for your constructive comments. There are some other factors that I haven't mentioned yet. Like for example both vans have rust in the plenum, under the windscreen and need work. The HX has rust around the rear tail lights as well.

The outcome of this thread has helped me identify if swapping the turret was firstly feasible and secondly achievable. My conclusion is that it is feasible, but a great deal of work that may not be completely necessary.

What I think I will do is get them both sandblasted back to bare metal so I can identify all the repairs needed and move forward on the basis of which one can be completed with the least work & $$.

Thanks again!