The answers....
1. Longwood Swallet, Mendip
2. Ariel Cave (or Blacknor Hole), Portland
3. Runscar Cave, Yorkshire
4. Boreham Cave, Yorkshire
5. Heron Pot, Yorkshire
6. Buckland's Windy Pit, North York Moors
7. Ogof Llyn Park, North Wales
8. Goatchurch Cavern, Mendip - ok I was naughty and put the elevation for that one!
9. High Pasteur Cave, Isle of Skye
10. Kents Cavern, Devon
11. Layby Pot, Derbyshire
12. Little Neath River Cave, South Wales
13. Manor Farm Swallet, Mendip
14. Notts II, Yorkshire
15. Mossdale, Yorkshire
16. Porth Yr Ogof, South Wales
17. Vesper Pot, Yorkshire
18. Sell Gill Holes, Yorkshire
19. Agen Allwedd, South Wales
20. Giants Hole, Derbyshire