after a couple of attempts trying to get new life out of old harness line boom attachments (not sure what you call the bit that actually grabs onto the boom), I've found some bits that seem to go together ok, The lines on the right are my latest attempt, lines on the left the previous attempt. Hardest part seemed to be finding tubing that is hard enough to not wear through in a single session on the water like the bunnings garden irrigation tubing does .

after doing some digging I found these guys
8mm (outside diameter) tubing
www.filtersystemsaustralia.com.au/fittings-connectors/tubing/3-8-rigid-high-pressure-tubing-for-water-filtration-3-metre-roll-568.html

12mm (outside diameter) tubing
www.filtersystemsaustralia.com.au/fittings-connectors/tubing/3m-john-guestr-12mm-bpex-tubing-caravan-watermark-hot-water-12bpex-50c-20-11wm.html

Today will be the first wear test (I'm using the 8mm tubing with old formuline downhaul rope through the middle), but so far they look great, and feel alot harder than what i was previously using.

Do they work?

I thought PEX was quite sensitive to damage by UV light. Is BPEX the same thing?