I always enjoy a trip to Chuan Spa in London. It's pure relaxation from the moment you walk in to walk or float out. The changing rooms are lovely and bright, fantastic showers and womens own steam and sauna. There are plenty of towels and robes and extra toiletries to use if you need them. The therapists are always great and will run through the whole treatment with you. The vitality pool and the extra facilities are amazing.
Make sure you add on afternoon tea to enjoy in the Palm Court for afterwards to finish off a perfect day.