I've decided to go for a double height card frame so that I can use my 14-slot backplane in the bottom half and put floppy disk drives and the PSU in the top. I'm now also able to fit proper Vero panels to the boards and lose the curtain rails.
Powered up and it works !
and some more boards fitted:
As I've lost one of my 6502 boards I want to save the original Acorn board for the System 1 so I have wired up a new 6502 board for the card frame system:
Finally the cassette interface is working (after fitting a new drive belt to the cassette recorder):
So that's a working System 2, next to upgrade to a System 3, but then along came some replica System 1 Boards . . . .