The standard sidelight looked very orange especially next to the xenon dipped headlights. The xenon headlights burn with a colour of 4300k, the standard sidelight bulb about 3000k which accounts for the difference in colour.
I found some warm white led bulbs on eBay that burn at 4500k and that claimed to be error free canbus. In fact when they arrived and fitted were a good match and canbus error free.
Extracting the bulb holder to swop the bulbs was the hardest part of the job. You need very nimble fingers to grip the holder and manoeuvre it in and out of the headlight casing ….. but pleased with the end result.
MG ZT info mods and maintenance 