In reply to Dave McKechnie:
I was in a university club and I got a bunch of experience by sending an e-mail to the mailing list offering a free session outside under the heading of something like "advice" or "experience" (I forget exactly) rather than "instruction" in setting up anchors for top-roping and getting some climbing done on the local crag (I borrowed some friends harnesses and extra ropes). There was a surprisingly huge amount of interest. I didn't go into lead climbing because almost everyone was really at a beginner level. Because it was done as part of a university club and really under the same guise as happens on every meet in a uni club where new members learn from older members, I was fairly confident that I wouldn't have to worry about unpleasant legal nonsense.
A lot of uni clubs don't require you to be a student at the uni to become a member, so you could potentially go down this route.