Cheers Guys,
I was actually getting worried about freezing as I thought my trackbike might have used water only but thinking about it I remember seeing a colour in the header tank anyway (but its not easy to get one's nose in there -
).
I kinda like to do the right thing so will be looking to use Demin water and a enhancer of some sort since it did run a little hot at times.
Silkolene do there own product:
"Pro Cool – Advanced all season non toxic engine coolant
This road proven coolant gives winter protection down to –34C and improves heat transfer making it an ideal summer coolant."
I guess there are plenty of others. Now I guess its time to pull the rad off and give everything a good flushing anyway.
Good point by Shazzam (as always) about the water pump seal lubrication - how much more likey would it fail using just water I wonder?
Many Thanks - Frank