Gary, this looks superb even unpainted!
The only thing I would mention - although, probably impossible to correct - are the soldering marks on the PE parts. Maybe add some more to make them look like welding/casting marks? If such existed on the real vehicle at all, that is.
The PE boxes and above all, the aluminum tubes really add that special something. I haven't seen such tubes being used so far but to be honest I'm no where close to being somebody that could talk about Churchills's

Excellent work! Keep us posted on the progress, please!
Cheers,
Cristian