In reply to Dave 88:
1) You don't NEED a qualification. Guiding is not professional in the UK.
2) Are you being paid in any way shape or form or is this purely a jolly? If it's purely a jolly and you are all going as equals on a non work related trip away, then you are not responsible. All adults should be responsible for their own actions and they would have to prove serious negligence on your part.
3) If it's a paid trip, then you need to follow best practice at the very least. MIA would be best, but a min. of SPA and ML would be advisable. Don't know about caving.
4) No bolts will not be rated - this is not industrial rope access work - infact access to the quarries is iffy and not legal, so FFS if you get caught by the quarry owners do not under any circumstances say you're with a company, or that you are being paid...