It's going to be a piece of work to bring that back to one trunk though. It looks like a loooong while ago someone pollarded it and then didn't take the crop and it just grew thicker and now the branches have started to grow into each other. Lot of rot showing too.
If it were me cropping it for basketry, I'd take it right down; thing is though, that's going to create a stool, not a pollarded tree, iimmc. Fine for someone cropping often, but otherwise no height to a 'tree' and if it ever gets left in the future it'll be a worse mess when it grows. That's called short rotation coppicing, which is different from pollarding to reduce height and breadth of a tree, and from the long rotation that produces good sized timbers.
Either way I think you're going to have to prune with forethought in the next few years to get something decent from the trees, even if it's just healthy growth.
10 of them ? You're going to be a busy man
Wonderful resource to have though
atb,
M