Finally . . .
I started out on this, the final leg of the project, believing that I would be able to fit everything into one box only 205mm x 155mm x 75mm . . . Hmmm?
I modified the transverter, I configured the PLL board and tested it . . . Yes! Sure it’s going to fit! I told myself. But only just!
I never throw out hardware, like nuts, bolts, washers . . . metal pillars. I found four, only four, tapped metal pillars that just happened to be exactly the right height to mount the PLL board such that it straddles the PSU board, just clearing the electrolytic capacitor. With the two halves of the box put together there is little more than a millimetre between the PA and the two right-angled SMA connectors carrying the 10MHz reference and the 135MHz RF. I think it looks good.