Photos of the derusting process. Have now got the dash top, scuttle top, and top half of the firewall done. That's just about enough to get the zinc paint out for but am tempted to do the front flanks, engine bay, and nose piece first.
The supplier said to be sure I degreased properly, hence the tooth and washing up brushes. I also rinse with water and a dish cloth before the rust killer goes on and on the final wipe down with kitchen paper the paper stays clean. Could argue not really necessary, and tests on "fluffy" bits of the chassis have shown that just slapping it on the end result is all but the same but I do want it to last and the extra steps don't add all that much time.
Had a "daylight look at the early rad shell and it really doesn't want to fit.
David