I find the original Wilesco grey(s) extremely hard to match, with the standard spraycans available over here, if a perfect match is a must.
The base-colour can be matched relatively good by eye, at least when we´re talking the later years without purple added.
But hitting the sweet spot with the right amount of metallic effect, that´s were the real challenge emerges.
All of the brands i´ve tried out, has either too much or too little "glitter", to match the original.
Next time i get one on the table, that is worth some real attention, i´ll try bringing the engine/base to the local automotive paint shop, and ask them to mix a match for it.