Just replaced mine after new rad & thermostat install, purchased coolant from local Mr T used 3 x 5 Ltr's @ approx £18 + vat per 5 Ltr now branded "Long Life" comes in 2 pre-mixed variety's Green = UK spec, Red = Import spec according to Mr T
This is a gr8 idea the coast/miltary road is excellent & Ventnor esplanade was the venue 4 a hill climb back in the day + there's a superb bit of tarmac from Sandown 2 Ryde via Bembridge Airport.
Look forward to my 1st IMOC trip & meeting up with everyone count me in