In reply to pork pie girl:
I did a lot of kayaking in the past, on a 3 month trip I woke up with pins and needles in both arms, hands and no senation in legs. Later after not kayaking much and a trip to Font it came back as you've described, rested and it went away untill 2nd trip to Font. I went to see a Doctor and they did the usual batch of blood tests, diagnosing everything from a Calcium deficiency to bowel cancer (not joking) for what turned out in the end to be entirely posture related.
I would reccomend booking in to see a good quality sports physio that understands climbing, follow a course of rehabilitation excercises and have some sports massage, making sure that you look at the root course of the problem, likely to be tight muscles applying pressure to nerves giving that pins and needles sensation. You might be able to get it through NHS, but it's much quicker if you just book in to see a physio and the money will be really well spent if you nip the problem in the bud early.
Hope this helps, don't be scared of the process of getting it sorted, it will reap its own reards if you do.
Oliver.