Hi' GeKK,
I'm sure this is the hotel that has just recently opened a short distance from the Mathraki Apts. If you go to this map on the main Arillas website you will see the location of the Mathraki, the Thetis is just down the lane a little.
http://www.arillas.com/map/I walked past it in the daytime everyday when I was there in June, it was very quiet by the pool area and being new the whole place looks gorgeous.
It is in a lovely peaceful situation but not far at all from the bars & tavernas, if you continue down the lane shown on the map past the Mathraki and then the Thetis you will eventually end up at the beach. On your way you will pass quaint little smallholdings with goats and turkeys!
We are going again in September and I have promised myself a visit into the Thetis to see what it is like so I'll say hello! (we are staying in the Mathraki)
I'm sure you will have a great holiday,
Eileen.