I can suggest you one thing. You can use Google Street View to see which streets and which buildings have Movistar FTTH Coverage.
How?
If you see a black box like this on the building wall, it is sure that it has Movistar FTTH avaibility.
https://maps.google.es/maps?q=las+palmas+gran+canaria&ll=28.466503,-16.248951&spn=0.012337,0.045447&hnear=Las+Palmas+de+Gran+Canaria,+Las+Palmas,+Canarias&t=h&z=15&layer=c&cbll=28.466518,-16.257148&panoid=nJ80bte2h_PyKMPR7dRCxA&cbp=11,17.82,,1,-32.03
Or like this:
https://maps.google.es/maps?q=Gran+Canaria,+Las+Palmas&hl=es&ll=28.131074,-15.424762&spn=0.012376,0.045447&sll=28.465598,-16.250238&sspn=0.027352,0.061798&oq=las+palmas+gran+canaria&t=h&hnear=Las+Palmas+de+Gran+Canaria,+Las+Palmas,+Canarias&z=15&layer=c&cbll=28.131069,-15.432951&panoid=QsmoOIvpLDBUx0iwgcKH5A&cbp=11,103.67,,1,-10.16
As you can see on the pictures, Movistar also use a red cint for the cables of optic fiber so you can recognise it very easy!
But there's a problem. The problem is that not all images in Google Street View for Las Palmas and Santa Cruz are recent. And Movistar FTTH installation in the islands began from the 2012 to now. So check carefully if Google Street View images of the street that you are looking for, are from 2012 to now.
Hope it helps you!
If you could move to a different Spanish Island like Palma de Mallorca (in his capital: Palma) there is a lot of Movistar FTTH there! Around 65% of the city is covered with FTTH. You can check it on Street View.
Greetings and i wish you luck!
