Being late as 1970, it may take time, but using the age at death in the GRO death index, look for deaths giving relations names of the deceased or obituaries in newspapers, address in local telephone directories, electoral registers, Will probate records to find the husband or wife's first name. The marriage certificate if it can be found - will give the fathers name. If the deceased had known childrens age, their birth certificate will name the deceased's spouse if the deceased was married.
WW2 marriages did have couples who married from all parts of the UK and abroad so it could be difficult finding a marriage.