I wonder if you guys from other parts of the UK are aware of the Grampian Speleological Group (GSG) caves and mines database which can be found at
http://registry.gsg.org.uk/sr/registrysearch.php
This allows you to search within 10 km (or 5 or 1) of a location - NGR or selected off the map.
A new feature has recently been added which allows search by a combination of attribute (ie cave, sea cave, arch, mine, tunnel etc) and length.
On the down side, a significant proportion of entries have little info apart from location and name - but it is getting better as more people submit info.
Also no photos or other graphics yet.