Replying to myself here.. just in case it might be useful to anyone else who lives in Las Marinas, in Denia.
I just signed up with IPOK telecoms, who have a shop called 'Central Phone' in Denia, behind the big Casa store on the left hand side of Partida Madrigueres Sud, going out from Denia to the motorway.
They have red/white signs all over Las Marinas and Las Rotas advertising fast broadband internet.
Just had their 'Wifi Plus' (wimax) solution installed, and the engineer's PC showed signal strength and quality of near 100%, but I have line of sight view to Denia castle, where the repeater is installed.
I'm can (technically) get max 6Mbs download, 1MBs upload.. fast enough for HD youtube.
Of course when it rains / lots of people using it, it will degrade, but sure beats the 1.2Mbs from ADSL on a sunny quiet day.
Installation is 145 EUR, 5/1 Mbs download/upload is 39.90 EUR P.M, 8/2 would be 55.90 EUR. But you would have to be nearer than 2K to Denia Castle to get the 8/2 speed.
It took 2 weeks from signing the docs to getting the installation engineer on site.
Visitor from the future: feel free to send me a P.M. to ask how reliable it is turning out to be, as it was only installed today. But it is working reliably at this very moment.