Hi, not sure whether this will help, but like you we visit Lanzarote as often as possible
. We live in the U.K. And have phones with 3. With this company they have a list of countries where you can use your data allowance, phone and text minutes just as you would in the UK. Spain and therefore Lanzarote are on the list. When we land we restart the phones (which then show Movistar as the carrier) and off we go! We don't pay any extra unless we are calling premium or Spanish numbers, which is basically the same as at home. I would add that we're not technology junkies, but we do check e-mails, the bank and sometimes the news. We don't have internet in our villa but seem to have a good connection in PB, though we are close to Montana Rioja (not sure whether this makes it better or worse).