Hi Louise,
The Hotel Sensol Spa does offer spa days. A friend of mine rented our apartment in February for a week and visited the spa - the cost was around 21 euros for the full day. She said it was absolutely fabulous - the pools etc were all lovely, and the price included bathrobe, sunloungers, fruit juice drinks etc. The treatments were extra and some had to be booked in advance but she managed to get a massage for an hour at a reasonable cost.
Not sure of contact details but they do have their own website.
Relax and enjoy!
Debbie