I went to Martin Maxey on the recommendation of a MNer, and saw Minal. She was lovely, very easy manner, and she did a fab job, better than when I went to a Shivata brow bar. Pretty pricey, but also very thorough and done in a private beauty room, I couldn't face getting myself de-furred on the main concourse at House of Fraser!
Same here in west London...I only pay £3 - department stores will often charge £15 plus! When you arrive, have a wander round the local salons and you will find one pretty quickly, or they will know where you can go.