In reply to Nicola:
Not my speciality but here goes.
Does kind of depend on which joints (MCP,PIP or DIP and then what structures)
Two main types of taping, circular and figure of eight. Archive some 'climber' magazines for an article with pictures. The figure eight should support the collateral ligaments, extensor hood and capsule a bit more, but is a bit more fiddly to apply and the difference may not be massive. In terms of joint hypermobility the pull of the tendon and pulley would subsequently stress the capsule and joint, and crimping on hyperextended DIP's or PIP's will really stress the joints.
You should only tape symptomatically, ie when you are sore, otherwise you should not apply the tape to allow natural strengthening of the structures through climbing. Controlling the frequency, intensity and type(indoor/outdoor/bouldering/routes/open hand/closed)may have a significant effect here. Part of your problem may be living in Bucks and bouldering with those freaks at the climb! (open hand outdoor clibing good!)Lumbrical and interossei strengthening may also help somewhat.
Good Luck!