General histories are always useful for background information
The National Library of Scotland digital.nls.uk/british-militarylists/archive/88735803 Free digital images of the Army Lists, though with fewer details than earlier ones.
The Home Guard home-guard.org.uk An excellent website dealing with the general history during the Second World War. There are also an increasing number of sites dealing with local units.
BBC / British Armed Forces
www.britisharmedforces.org Both websites have oral history testimonies and photographs from men and women who served in the Second World War and immediately afterwards, including National Service.