You should start with his marriage certificate. This will show you his father's name and occupation, though you cannot always rely on this information being accurate. A Thomas KEENAN birth was registered in the fourth quarter of 1915 in Prescot RD, but you should get the marriage certificate first because, without the corroborating evidence from his marriage certificate, there is no way to know if this is the right Thomas.
Make sure you get the certificates direct from the GRO (
www.gro.gov.uk). Third party suppliers will try and charge you considerably more than the statutory £9.25 fee. GRO references can be found through
www.freebmd.org.ukCaroline