I have a friend who rents a table and reads Tarot at the big indoor marketplace in Camden Town. I believe she is there Thursday through Sunday. I can't remember the name of the market, but it's the very large rambling indoor/outdoor market about 2 blocks away and across the street from the Camden Tube station right next to the locks. She is usually on the ground floor of the main building.
Hi, well, I don't live too far from you, as it goes, and could give you a reading. However, I can recommend a chap who sits upstairs in the Camden Lock complex. Not the big hall with the shops, but the smaller hall off there with the stalls. He sits in the corner and sells Tarot. He is good. I also know an excellent Tarot centre, but in Dartford (where I learnt Tarot). In town there is the College of Psychic Studies, in Kensington. They have good readers there. In Burnt Oak I know someone too. Also, try going to 7 Dials, and Mysteries, they could put you in touch with good reader. Other than that, I can't think off-hand of others.
As I recall, there's also a pub/restaurant with an astrological theme very close to the Notting Hill tube that I've been to. There were several readers there doing very casual readings. I believe the name is the Twelvth House or something along those lines.