first thing is to order copies of the register entries - The Father may have been declared if you are lucky

Births Jun 1938 (>99%) Gloucester C. 6a 550

https://wwwDOTgovDOTuk/order-copy-birth-death-marriage-certificate

if not declared, you may through DNA pick up non-recognised 3rdcousins etc and start to track back to your "man/men"