Sorry giggles, didn't realise that was the situation.
As I understand it, an employer can refuse or change their mind about holiday leave provided they give the appropriate notice. If there's nothing in your terms and conditions, the notice period should be at least twice the length of the period of the holiday.
If you lose money, because you've booked flights or a package holiday, you may in theory claim compensation from the employer.
It might be an idea to contact the ACAS Helpline 08457 47 47 47 (08:00-20:00) for detailed advice.