Thanks! I remember that cover now! The article has both the hex and the asm listing. I think I did an update to it to use the bank switched memory on the 128K to get 8 16K Spectrums.

Of course with something like a MGT +D with the 8K ROM and 8K SRAM it would have been possible to use the NMI button to switch between two 48K Spectrums on a 128K and have them run a game in one and BASIC in the other.