DVLA does not give models, only the makes, but those sites which piggy-back DVLA data all seem to use TX1 on a sample of plates. However the book is a good one "A Century of London Taxis" written by Bill Munro - a black cabs expert, with some specific detail for the anecdote: Manganese Bronze's chairman Jamie Borwick suggested Fairmile, but Jevon Thorpe - the TXI designer and Managing Director of LTI - created the TXI name with his Big Senior Management pen. So I believe the book.

We have a few comments down the years which reference TXI, but not enough of them to mount a campaign and nothing which seems to question whether we should be using TXI or TX1. I suppose if the whole world calls it TX1, probably too much grief to resist??