I seem to have opened a can of worms here so let me explain.
I've no intention of re-inventing the wheel, it's just something I want to do and as I said, it might work it might not. I'm not sure running a CS at such high temperatures is such a good idea and I favour running one a bit lower, about 65-70*C
My plan is to run the coolant through a domestic heating radiator, or into a hot water tank, or maybe both. But in the circuit I intend to fit a car radiator with an electric fan as a safe guard against melt down. The car radiator will be insulated to prevent unwanted heat loss and have air flow operated flaps to allow the fan to work.
So there you are, that's my plan.
Rob