Good idea Ian.
Let us know how it goes. I have found that as the 2 pipes pull apart, the tear tends to run askew and cause splits in one of the pipes - might just be me being over enthusistic/careless/manly.
All going well so far. We have only used the parted section that the hosing has straight from the packet. What I'm trying to say is that we haven't tried to part the two tubes any further from as they arrive from Fresenius.
*also just looked up the hosing in the Fresenius catalague to purchase as a spare part - £100!! so if anyone has any hosing contacts out there let me know!