Hi Steve,
this is an interesting thread,
yes it is an HMV 903 and I think the only one in existence. It is listed in Steve McVoy's database with no name given for the owner.
http://www.earlytelevision.org/prewar_database.html
A Marconi version of this set (Marconi 704) recently changed hands and can be seen working here:-
https://www.youtube.com/watch?v=TVQutdYBsgM
David - I think your post is entirely relevant. Given the short broadcast times of pre-war television, the owner of an HMV 903 would surely have been upset to find that only a few months later their set had been superseded by the HMV 907 which had a smaller cabinet for the same screen size, included a radio and was quite a bit cheaper.
Cheers
Andy