Thanks for the link - no I do not have any cable guards - never even seen them in the UK. The cable is taped and cable tied to the pipe, so not too worried about that, but the pipe could get damaged (the well is sleeved with steel pipe to approx 20ft (which happens to be the water level) - below that it goes through chalk which is self supporting - the well is 60ft deep, the pump at about 40ft). Next time we have the pump out for repair/replacement/maintenance I'll look at getting some guards. I would guess that the pump swings way below the water line, and it just scraping against the chalk, creating a bell shaped chamber at that point... The old pump failed some years ago (it was second hand and the casing rusted through) - it didn't show any sides of damage to the sides - the new pump is stainless steel, smaller in diameter (and longer) - the pipe seemed OK when we changed it, but it would be better safe than sorry...