I replaced coolant in my car when new aluminium radiator fitted a few years ago. I used Mannol AF12+ which conforms to Ford spec for my Roadster and is available in 20 litre containers. It can be diluted but also used as is with freezing point of -40°C. This I confirmed with my refractometer and also that it matched the OE coolant. It has a minimum service life of 5 years.
Note MMC usually specify Morris lubricants and coolant as they appear to have a long standing association with the company.
New expansion tank if needed
here.
