As the above poster state you can order a copy of the birth certificate as you have a DOB and name it should be easy to find the correct entey in the General register office index and then order a copy.
The birth certificate will give you the name of the father - if he was present or married to the mother, the name of the person who informed about the birth/registered the birth. The name of the mother and any former names. The place of birth and the occupation of the father.
Using the GRO index - which are indexes of births marriage and deaths registered from 1837 - 2005 - you can search for a marriage of the man - if he married you can then again order a copy of the marriage certificate.
A marriage certificate will give you the age at marriage, the occupation of the bride and groom, the addresses of the bride and groom at the time of the marriage and the names and occupations of the fathers of the bride and groom. The marriage would also have two witnesses, they may be family or friends.
With an address from a marriage certificate you can look through electoral registers to see how long the people where living at that address - but you will probably need to visit the archive that hold the electoral registers in that area or pay for this to be done.
You can also search for children of that marriage by entering only the surnames and hoping there are not to many with those two surnames producing children.
The GRO is available online at various websites but you will need to pay to view the results - certificates are not online and they cost 9.25 to buy and you order from the GRO directly using the reference numbers with each index entry
DH has recently found out the name and DOB of his biological father. He has no interest in getting in touch with the family (if still alive, his father would be very old now) but he is interested in finding out where he came from and a little bit about him. With just a name and DOB, where can we start and what could we realistically hope to discover?