Thanks for the info about the liveried MG sold online. I’ve had a look and kept a few images for future reference.
I did have a search a while back to see if there was any contemporary evidence of MGs with the RAF, but I found nothing.
There was a David Brown roadless on tracks but apparently it was found to cause too much damage to the airfield and was subsequently converted to tyres. I have a photo somewhere when I find it.