Gizzaclue?
Trying to order coolant. How much space is there to fill?
While we’re at it , although inhibition of corrosion might be best achieved with a maximum concentration of coolant (50:50). What is the best concentration for heat transfer?
I found it’s all about volume of water, the more water you have, the cooler the system will run. My S1, has a 9 litre charge cooler tank in the front of the car and I’ve never had any charge temp issues ever. I know what I have is excessive, but the theory is the same. More is pretty much always better.
Also kills understeer. 
win win
Ha.
Sage advice Sean. Well as no one has numbers, I’ve bought enought coolant for 15litres at 50:50 (the Elan uses the same stuff), so I’ll let you know.
About 5 litres (50:50 mix)…well that what I put in mine a few weeks ago.