Rick Hughes coughed up some electrons that declared:


You can get copper to MDPE compression joints in any plumbers merchants

Brilliant - thanks.

... and fully acceptable to have them buried ... just cover with pea
gravel wrap any exposed copper in Denso.

Excellent. I might combine this with Tom's ducting suggestion. The bit I'm
extending is only about 4m long. There's another probably 12m to the road
(takes the long route round a bend to avoid the trees). Re-threading the
lot with a single length of pipe when doing the 12m bit wouldn't be a bad
idea (One less joint near the foundations).

Thanks for that.

Cheers

Tim