I have an employee on an 8 month contract in the UK. Before starting, we agreed for them to take a 2 week holiday to go home to Europe (no problem here). They bought the plane tickets for their family. But now they are asking also for unpaid leave for 2 weeks' compulsory quarantine after returning, which I would struggle with. I'm a bit stuck about how to handle the situation, any suggestions?
They have a holiday allowance, which is theirs to use, and it's fair enough they want to go home for 2 weeks. As is, I will find it hard to manage without them for 2 weeks, but that's on me. If they do go, they will also have to take compulsory quarantine upon return. 4 weeks absence is too much though, especially on an 8 month contract (which, due to the nature of the job, is unlikely to be extended).
So I'd like to say 'yes' to the holiday, 'no' to the extra 2 weeks, but they already bought the plane tickets. Normally I'd say, if I'm asking an employee to cancel a holiday, it's on me to cover the cancellation cost, but I'm not taking away their holidays. Do I have any other options? Ask the employee to find cover for the 4 weeks themselves? The job can only be done in-person, so no remote work arrangements work. It is expensive and problematic to find ad hoc replacement for the employee.
EDIT
To be clear, the holiday is in the future. It's not that they got back and forced into a surprise quarantine.
EDIT
I see this question attracted a lot more attention than I anticipated - good I guess. My question is well-read in conjunction with @motosubatsu's answer, which I think is excellent. The fundamental issue is that neither straightforward approach is OK. It is not OK for me to stop the employee from going on their well-earned holiday. It is also not OK for an employee to turn up and announce "We agreed a 2 week holiday, but actually I'll be away for 4 weeks, sayonara". That a compromise is needed is obvious, but it's not even clear what that looks like. Taking a principled stand and looking at it from a single point of view, like "you cannot stop your employee taking a holiday, period", or "just fire them" is missing the point of the question.
Many thanks for all the responses, especially those that do not assume evil intentions on my side.