Carrying over annual leave

Due to the war, my holiday at the end the end of this month- into start of April has been cancelled.

Our trust sent out a letter saying they will support staff etc..

I’ve been told I can carry over 5 days AL but it’s also managers discretion, only for exceptional circumstances.

My manager has said no..as it isn’t exceptiona.

It’s for my 50th Birthday and need the holiday now to book for next year..is there anyone else I can raise it with? I’m absolutely furious