We visited Ranwell as part of a larger trip around Sri Lanka. The visit started with a 30 minute tour around the gardens where it was very interesting to see where our spices come from. We then were taken into a shaded area and shown all the products they sell. No real 'hard sell'. We were then offered a massage which was nice and relaxing.
You then 'exit through the shop'. We were not hassled and we did buy some after sun cream which was well worth it for the rest of the trip.
Worth a visit but expect to buy something.