MDPE pipe offcuts (Middleton St George, DL2)

I'm building a poly-tunnel and need to source four more seven meter lengths of strong but bendable pipe for the arches (I have one already).

the pipe will fit over scaffolding poles so it needs to have a 50mm internal diameter. 63mm MDPE pipe (gas or water) is ideal. Other similar dimension pipe may also work.

Reclaimed/dug up, off cuts and part rolls are all good.

Advice on where I might source would also be gratefully received.