@Shytot I paid £100. A few years ago I paid £70 for a local residential locksmith (back in Essex) to open a front door (keys locked inside - bit of a pattern forming here!) so £100 for a vehicle specialist seems OK to me. He did say it was a bit more than normal because he had the best part of an hours drive to get to us. Maybe someone else might have been a bit cheaper but this guy was responsive to initial messages and sounded good when I spoke to him on the phone so I didn't spend any more time ringing around.
As it was all done so quickly and without any drama I also didn't lose the last day of my holiday.