Alexa in Ladbroke Grove/Notting Hill (lots of reviews on here) might hit the spot, although she is now well into her 60s, which may be more mature than you want.
I first saw her years ago, and continued to do so on and off until around 2005, and from the reviews here she still provides the same service: nice (naturist) massage and excellent BJ. She's also interesting to talk to, and is a real wine connoisseuse: we shared a few bottles of red wine over the years.
One of these days, if I can get to London I shall renew my acquaintance.