Hi John,
You are too good for me
After you said that the T 293 had a rectangular tube, very faint bells started to ring! I vaguely recall that in the batch of Ekco tv's, one had a broken tube neck and was dismantled. The back was then used on the set I thought was a T293 just to confuse me.
Sure enough, I've just checked and the T293 back has a remote control socket!! I dug out the scrap chassis and lo and behold, it also has a remote socket. So that mystery is solved.
On removing the incorrect back and inspecting the set it has a round Mazda CRM 141 tube and the date on a capacitor is August 1955. It also has two aerial sockets mounted very close, side by side. I am guessing one for band 1 and one for band 3??
So there you go, is it another T221?
Cheers
Nick