Thanks Mike, that's a good theory and seeing three together, one with pretty good SA provenance lends credence. Keep our eyes peeled for further evidence of a SA link.
I think your theory on his path through RAC - 146RAC - RTR is perfectly valid. Interestingly 146RAC carried on well after the war and was the last converted RAC regiment in existence, being disbanded in Feb 1947 at Ahmednagar.
It would be wonderful if Capt Tom's imminent autobiography shed some light on this kind of stuff...
John