Holiday allowance while off sick when office is closed

Hello,

I’ve been searching for an answer for ages on here and on google and I can’t seem to find anything. I am currently off from work with a gp for note that covers me until jan. our office close over Christmas and we are expected to take those days off as holiday which is no problem but as I am off sick where do I stand with getting these back. I know they normally give holiday back when you are ill but never been signed off over Christmas before so I’m not sure where I stand as the office will be closed anyway.

Thank you