I will be staying there in September and emailed them about the shuttles. This is the information I got:
We are pleased to inform you that our hotel has a complementary 24 hours transport , on request , from and to airport.
The bus is running every hour from 6.00 am to 11.00, depending of traffic and availability.
From 11.00-17.30 on request, please phone 00 34 91 206 34 10.
The bus is running every hour from 17.30 to 23.00, depending of traffic and availability.
Later than 23.00 on request, please phone 00 34 91 206 34 10.
I'm pretty happy with that response.