What's holidays entitlement for postdocs in the UK?
Maybe you are thinking you need to take a full 24 hours of vacation to get the day off?
Typically you take hours off for your working hours (I'm in the US but I can't really imagine this being different for the UK; also the math works out). So for a job as stated where you have a total of 36.5 hours of working time per week, 219 hours would then be exactly 6 weeks (aka 30 work days) of vacation, which you can take in whatever increments are suitable (say, 4 hours if you need just half the day, 7.5 hours for a full Tuesday, etc). There might be some limits on when this time can actually be taken to not conflict with certain job responsibilities, but given proper notice they should accommodate your requests.
It would be reasonable to clarify exactly how vacation hours are awarded and taken (I'd search on the university website for some regulations before asking someone about it) but the numbers stated seem like they fit with the &quot;30 days&quot; in the job description.