We inherited bamboo when we moved to this house. We used a combination of digging, digging and yet more digging using garden forks / spades and pick axes (I can see that the kit used by Rainwater Fanatc would be good as well). I think the overall dimensions of the rootball / rhizome mass eventually turned out to be about 4 metres by 3 metres. We also used glyphosphate as soon as little bits started to show their heads above ground.
It was a bit of a nightmare but we did defeat it in one season with a bit of help from our neighbours. The bamboo had spread under the fence and was lifting their patio so they lifted the patio and dug and sprayed for a whole season like us (bless them).
Just the odd bit sprouting in the second season which was easy enough to pull out / dig up.
Good luck - it's worth the effort - I hate the stuff!!!