Managed to get a different version on ROMs for the board. Luckily, I did as up and till now the only version I had was for the Hi-Res board which unfortunately I don't have so if use it here it never would have worked.

For the build looking like I'll go 'all the way' with TTL ICs. There is some tricky timing happening so will be good to keep everything the way our founders intended then mess about with new technology

Still looking for that elusive Hi-Res card and 512k expansion. Here is the Hi-Res! wanted dead or alive. With install instructions please 😁