Henry T Midwinter appears on a travel schedule in 1927 and the address he gives is 38 Oxford Terrace, Hyde Park.
Maria Midwinter who appears with him on the 1939 register dies in 1944.
I cannot find any marriage for Henry to a Maria but he may have married her abroad.
There is a marriage for Henry in 1950, if this is the same one:-
Marriages Jun 1950
Midwinter Henry T Scott-Forbes Hammersmith 5c 1511
Scott-forbes Dorothy M Midwinter Hammersmith 5c 1511