This is a legit shop, in the basement of a salon across from Gloucester Road Station. They're supposed to be entirely above-board, though you might find one of the employees offering HR occasionally especially if the boss (JJ) isn't in.
JJ gives a fantastic Thai combination style massage, her style is moderately strong and fairly fast-paced; though she does not offer any extras, I have returned to her regularly for the therapeutic and mood-boosting effects of her angelic hands. She is a class act and opened her shop more for fun than for money, which she is not in great need of. She normally gets fully booked by mid-afternoon, so I recommend advance and/or morning booking.
Of her employees, I can speak of two:
-stocky, darker-skinned, short-hair Thai lady who gives an excellent deep-tissue massage;
-one short-hair, paler skin Thai lady who I strongly advise you to avoid.