I finally started receiving some parts, and started off tackling my heater box assembly and controls so I can get that out of the way.
Started off with fixing the heater control cables, the 55 year old plastic bracket was broken leaving one of the cables dangling and non-functional, so I fabbed a new bracket out of metal to reinforce the plastic, works good now:
Then I sandblasted all the heater control parts, flaps etc, gave everything a coat of paint:
Installed the new sealing foam kit, new extended tube aluminium heater core, re-assembled:
Unfortunately when I installed the original blower wheel on the new motor it was way too wobbly and out of true for my liking, so I ordered a new one and that'll be here in a few weeks.