Note that insulin is pretty temperature sensitive, and needs specialist shipping so that it doesn't end up boiling on a tarmac somewhere. That said, we found pump-compatible insulin on Phi-Phi Island in Thailand, so I expect insulin is possibly not the core issue.

The other things (like infusion sets) should be easy to ship. The UK suppliers generally won't sell them unless you have a UK pump and an account with them, though. It could probably be worked around though, using some sort of international forwarding arrangement.