In my experience, most companies give you a certain amount of holidays and you're allowed to use those holidays at any point, you don't need to accrue them first.
And if you tell them during the interview that you've got a holiday already booked and can't get out of it, they'll usually be very good about it and let you take it off or let you start after the holiday. Case in point: my last job I had, I started one week before my holiday, worked that week, took the two weeks off and came back to work. No problems whatsoever. Plus, they gave me those days off as paid holiday (the amount I would get for the rest of the year as I started that job mid year).
Just this February I took 2.5 weeks off for holiday. Again, no problems whatsoever. My company is very good about letting us go on holiday, they encourage it. It's part of the job, they can't expect you to not take it.
The work culture is very different here. The British love their holidays and no one gets in the way of it. Each company is, obviously, different but I think you'll find that on the whole, most companies give you those holidays for a reason - to take them!