See my link collection pages here. The individual changes are listed below.
Here is a link to the Nascom schematics again as a reference.
At this point, when I build the boards below, my Nascom still existed as the original board. The board was roughly the size of a DIN A4 sheet of paper. With the help of the Z80 buffer and the parallel bus cards shown here, I was able to move the Nascom piece by piece to a card system consisting of a couple of 100x160mm cards.
Recently, I purchased an Odroid C2 board with the intention to replace my current Odroid C1 board. The C1 is currently in use as my constantly running micro home server. The C2 builds upon the ARM A53 architecture, which is 64bit as compared to the 32bit A7 architecture of the Odroid C1. The C2 has 2Gb of RAM and the CPU runs at 2GHz.