Catman, to answer your question about serial numbering; it is true that as far as we know 1403 Trials rifles were converted to 4T's. However, Enfield made about 2,500 Trials rifles altogether, so only just over half of them were converted. Neither were they converted sequentially, so you could come across pretty much any serial number between 1 & 2500 when looking at a Trials T. One of mine is serialled in the 2000+ range.
Hope this helps.
ATB.