The censor marks CEN T SOR with the central T which could be another letter or letters, a number or a symbol are largely associated with ships of the Dover Patrol Command in WWI. The letter T is known in several forms and in purple, and provides scope for study - some time.
The cover has a London machine cancel dated 31 October 1917 with wavy lines, with an illegible censors initials. However the cover illustrated has, on the reverse a boxed PH. / 344, shown here enlarged by 150%.
I've not seen this before and I thought Peter High may be able to throw some light on it.....?
Cheers
Tony
Hi Tony,
Hope you are well.
The P.H. mark certainly is a collector mark, I have sen this applied to a broad range of postal history over the years, although I am not sure who the 'collector' was.
Peter
Peter - So it obviously wasn't you, maybe Peter High.... !
Hardly his style, Tony!
chrs
N
A bit over the top though. Other dealers do at least write on covers and cards in pencil