You were right on the money Louis. The starter was clogged up with clutch dust. Very well done and thanks again.
Still can't figure out why it worked when the engine was cold but not when hot, but hey-ho, all fixed now.
I believe your starter was only failing when hot due to the fact that metal conducts electricity better when cold. Could be wrong but I’m sure this is the case. I've the same problem with the E36 316i Compact at the moment, thanks for the info guys.