Some companies declare a mandatory shut down between Christmas and New Year - and then say the staff must book those three or four days out of their annual leave entitlement.
Surely that practice should be banned - if the company is shutting down for the duration, the company should absorb the days instead?
Possibly! Although many services, even those which are office based or who cater to leisure takers, don't shut down over the period, so it makes sense in the wider scheme of things to ask people to take holiday when others are having to work. Also if you work in an office you generally have no choice around the 8 bank holidays coming out of your allowance anyway. I have to book them out, since theoretically my NHS pay grade includes people who might have to work BHs and thus get the time off elsewhen, but because of my office-based role I have to take the BHs anyway. (I worked in Ireland in my very first job and there, Good Friday was not a public holiday, but my office closed down anyway. They paid us for it, but it came out of AL.)
From anecdotal evidence elsewhere some companies do add those three days to the AL allowance but with the understanding that it's taken anyway. When I was last looking for a new job (18 months or so ago), most companies advertised 25 days discretionary leave plus BHs, which would presumably include any days that you were made to take off after Christmas. You weren't gaining much but you weren't losing. But normal experience is that those 3 days come out of AL anyway and you just have to put up with it. (If you keep arguing this way, you end up with escalating demands -- if you feel you ought to have the full legal 28 days as completely discretionary, does the company therefore also have to pay you for shutdowns, including BHs? etc)
As it stands it's legal for a company to tell you when you can take holiday. It's certainly not the worst I've seen in the UK -- one landscaping firm competing with my late husband's employer had a holiday blackout from May to September inclusive. Sure, it's the busiest season for work and people in the industry, and sensible people work round their colleagues' dates. But it also happened to coincide with the prime holiday season for children and possibly emphasized the very specific gender roles in which any guy working for the company would have a wife to take care of any kids. The problem came when my husband's firm contemplated buying them out when the owner retired, and whether TUPE would allow the purchasing firm to remove the onerous contractual provision to match their own much more sensible policy.
So it gets complicated for employers and accounting systems and so a compromise has been reached. Personally I'm glad I'm in the NHS where I can trade those days for others at another time of the year and with WFH added to long service on my current contract I have more AL than I can actually use or need to use, but for the other 8 BHs I'm out of luck.