Thanks Mark and John.
Unfortunately yes John - I suspect a previous owner did some "alignment" on the TMB272...
I bought the TMB272 and TX275s almost 30 years ago, but only now came to working on the sets.
The alignment is now reasonable, but could be better.
The TX275 is an export model. I have a promotional sheet in Dutch, and found a mention in a French promotional booklet of British electrical products for the home, and a Swedish ad.
It would be nice to find some documentation of the TX275 set(s).
Jac