Thanks all - definitely not trying to take the proverbial with my calculations, but my extremely limited understanding was that we would be due back 75% of the fare paid, which
would include the taxes paid.
In terms of 1.6p valuation - this is what BA sell their Avios for, and as MCOL can't award Avios so I can't see a way for me to be "made whole" in any other way. As @
corporate-wage-slave has suggested, I think I will offer acceptance of an Avios settlement.