There are some good ones here!

Balls Cross, West Sussex.
Beer, near Seaton, Devon.
Blubberhouses, near Menwith Hill, North Yorkshire.
Blue Vein, near Box, Wiltshire.
Bottom Flash, near Winsford, Cheshire.
Briantspuddle, near Dorchester.
Brown Willy, Bodmin Moor, Cornwall.
Bullyhole Bottom, near Gaerllwyd, Monmouthshire.
Buttock, near Barley, Lancashire.
Cocklick End, near Slaidburn, Lancashire.
Cockup Bottom, near Bassenthwaite, Cumbria.
Cuckoo's Knob, near Wootton Rivers, Wiltshire.
Cold Blow, near Tenby, Pembrokeshire.
Dancing Dicks, near Hatfield Peverel, Essex.
Dog Village, near Exeter.
Donkey Town, near Camberley, Surrey.
Great Cockup, (mountain) near Bassenthwaite, Cumbria.
Great Snoring, near Walsingham, Norfolk.
Helions Bumpstead, near Saffron Walden.
Hen Poo, near Duns, west of Berwick-upon-Tweed. (name of lake)
Lickey End, near Bromsgrove, Worcestershire.
Lickham Bottom, near Hemyock, Devon.
Loose Bottom, near Falmer, East Sussex.
Pant, near Oswestry, Shropshire.
Pett Bottom, near Canterbury, Kent.
Piddlehinton, near Dorchester.
Pisser Clough, near Widdop, West Yorkshire
Pratt's Bottom, near Farnborough.
Sandy Balls, near Fordingbridge, Hampshire.
Scratchy Bottom, near Durdle Door, Dorset.
Slack Bottom, near Hebden Bridge, West Yorkshire.
Titty Ho, Raunds, Northamptonshire.
Tomtit's Bottom, near Cowley, south of Cheltenham, Gloucestershire.
Tongue of Gangsta, Mainland of Orkney.