How to find someone who clearly doesn't want to be found

Hello

So I am attempting to find my grandfather… well more likely more information about him. It has been very frustrating.

All I know is he was born Frederick Harvey Masters (07/09/1928) - I’m not even sure that is his correct DOB as nothing in the family tree is 100% accurate.. He married Margaret Rose GALE in 1951.

The marriage certificate says his occupation was R.A.A.F but unsure if he had an aliases.

Any help would be appreciated as I feel I would get more answers from a brick wall.