Summer Holiday Offer - Get 15% Discount Grand Sirenis Matlali Hills Resort Spa Mexico. Book your summer holidays at Grand Sirenis Matlali Hills Resort Spa Riviera Nayarit for stays from 1 May 2016 to 14 July 2016 to receive 15% discount and get relax with a steam bath plunge pool and six private interior and exterior palm hut treatment rooms. Terms & Conditions: Offer valid until 30 April 2016. Stay period is 1 May 2016 to 14 July 2016. Room Type: Tropical View Junior Suite. Book Now.