Here is his birth registration for the December Quarter of 1911 from FreeBMD

WILSON Cyril C W Wilson Caistor 7a 1192

Note: It has been mistranscribed , the C is G on the film.

There is another entry, that looks like some sort of correction but not obvious where from as there is no accompanying scan

Firth Cyril G W Wilson Caistor 7A 1192A

Here is his death registration in March Quarter of 1959 not 1957

FIRTH Cyril G W 47 Surrey S.W. 5g 1366

A copy of the birth certificate from the GRO at £9.25 (don't use any other method) will show his mother's name which should lead to the later marriage if and when it occurred. Incidentally if Cyril married it does not show under Cyril G W.