Rich, mine has never been driven any distance but has idled for a couple of hours non stop and never had any issues with the way it is plumbed (the same as the honda elise)
I have not installed the one way valve yet as I was told that I would not need it plumbed the way it is but hey I'll wait and see, I did remove the gobin on the top and replace with this
As for the coolant sensor I put mine here as it's very neat! Only took five minutes to tap into the blanking plug above the oil filter
