I notice that the £13 cover doesnt cover your ski's/ board, whereas the £17.60 policy does.
The rental places can charge you if you damage/lose their equipment.
This happens........Its amazing how many dropped ski's/poles etc you see when going up slopes on the chairlifts. For a Fiver extra I would have taken the next level of cover, as the recovery of these ski's/poles is sometimes near impossible!!!
NatWest Advantage Gold account comes with travel insurance. It was good for us a couple of years back when my son got stretchered off a mountain in France and received hospital treatment.
I don't know the exact T&C's but I generally keep around £250k in the account and it keeps them happy.
make sure that you read the terms and conditions of the policy VERY carefully as to what they will and won't cover. You will be amazed what they won't cover!!