Thanks Christine.
There is something special about looking at original documents that were written all those years ago.
Its really kind of you to offer to look further, but have checked the LDS catalogue and they do seem to have the relevant years for Branxton in their database so its doubtful that your time would be well spent.
I have Thomas' birth date confirmed via the 1939 Register and his school record - which also confirms his Dad's name. So, rather than have you check every parish register in the county looking for baptisms that may or may not have taken place, I'll bung him on the back burner for now.
That back burner is getting a bit crowded, but there's always room for one more :-)
Your efforts on my behalf are really appreciated.
Boo