There is a singaround at a small village pub just to the east of Luton on Saturday evenings (and most Tuesday evenings, which is when I go). It's in the Beds/Herts permathread (check there in case something comes up and it's cancelled).

The Plough, Plough Lane, Ley Green, Hitchin, SG4 8LA

Starts around 8:30 and goes on until everyone leaves, usually 12-12:30 on Tuesdays at least.