KARFA

I think you could try file a claim. It is certainly within scope of the 14 day period. Obviously the more contentious bit will be whether BA can show the cancellation is caused by extraordinary circumstances which could not have been avoided even if all reasonable measures had been taken.

I expect BA will just deny your claim "due to covid" and you would have to go to MCOL/CEDR to have any chance to get anything.

I don't think MAN T3 is reopening soon btw? The last I heard was maybe June/July?