Clive,
If I remember correct, this should be AL-14 Methanol, Technical, Specification BS 506: Part 1, 1987. Described as Methanol, methyl alcohol, for industrial use.
When the container is filled, it is drawn in through a very small bore tube, so I would not have thought it to be in sufficeint quantity to harm anything as it is in vapourised form to prevent freezing of any moisture in the system. Sounds like the wrong fluid was received, all army vehicles have had this fitment for many years and I never came across, or heard of problems with valves.