Employer used my annual leave on days that I am off

In England, been here just under 2 years.

Year starting off well...I work at a small ish business that is open 7 days per week. I am usually in charge or sorting out the rota, which is fairly straight forward as most people have the same days off each week (including myself). I work 5 days a week, 40h, sometimes a little more as overtime which is paid at normal rate.

Recently business was closed for a couple of weeks and employer asked us to take annual leave for this period, which is fine, except instead of using 5 days per week of annual, leave employer allocated 7 days per week as annual leave on the official rota and when asked claimed that it is not possible to have days off since the business was closed anyways and annual leave to be used this way.

Please could anyone point out to me how I can make it clear to them that this not how this is meant to work?

This is not the first time I have had an issue like this at this workplace, usually when money and payment is involved, so in all fairness, I am not too worried about being dismissed etc.

Any advice would be appreciated!