Massive thanks for labelling the pieces @Jasonb, it makes things much much easier.
I’m not entirely sure what part of the eyepiece you want measured. It says moon on one side and, once you remove the little plastic cover, 6mm on the other.
I’ve taken a pic of the other mirror and it seems to be in similar condition to the first.
It’s rather a long shot but I’ve contacted the community warehouse place that sold me the telescope to see if they had the legs lying about somewhere. I’m fairly confident they would be handed in with the scope but, given that they described looking for them as akin to finding a needle in a haystack, I’m not hopeful they’ll be found. I’m to call again mid week. Fingers crossed.