Cheers, Gi.
From what I understand, there's not much hapkido in the UK. There seems to be a fair amount of Japanese or Japanese-derived jujutsu, though.
Given that nearly all hapkido schools emphasize an extensive kicking repertoire (but not ours, as I mentioned), you probably would not find it kind to your knees.
But there are other elements of the art that can be hard on the knees if you have any problems. For example, our way of doing throws and takedowns focuses on using the body (energy coming from what the Koreans call the danjeon, or tanden in Japanese). To do this efficiently, you have to bend at the knees a lot in many techniques when throwing or taking down an opponent. I experience knee discomfort in training fairly frequently. But, I'm also older than the average student, so I'm dealing with the normal wear and tear on the knees that anybody at my age (55) probably experiences.
Anyway, I'm glad you found the info about our hapkido useful. And good luck with your rehab and ongoing training.
btw, if you're interested, here's a link to our Korean website. The English section has extensive information about both hapkido and kuhapdo (our sword art, which is entirely separate from our hapkido curriculum).
http://jungkikwan.com/I'm heading to Korea for a week and a half of training in less than two weeks... and as usual, that little %$#@ Kim Jong Il is acting up just as we're about to go. It never fails.
