An excellent “how to” is provided at ….. https://www.the75andztclub.co.uk/forum/showthread.php?t=645 as to removing the original blank and adding the cup holder. Care is required prising the face label off the unit – I carefully pulled the face off using my fingers pulling on the bottom edge.
The problem I had was that there were some wires bundled at the back of the holder cavity preventing the cup holder unit to fully click onto place so I had to remove the lower half of the centre dash to release the wires.
MG ZT info mods and maintenance 