Thank you for your suggestions - much appreciated.

A trench sounds a good idea though it will mean taking up part of the patio which I guess I had expected to have to do in order to solve the problem.

A metal collar may also do the trick, though the shoots if they are coming from the root, may not solve it completely. I could dig a cement trench as well as place a metal collar.

I'm a little wary of using Roundup as I really don't like using weedkiller due to there being a lot of wildlife in my garden, as well as my fish and I'd like to keep my bamboo somehow, even if it means having to dig it up and replant elsewhere.

Thanks once again for your advice.