You are correct.  The FREEVIEW boxes are for terrestrial channels - about 30 or so in the area see
http://www.tdt1.com/canales-television-tarragona.php?dem=tortosa
you need an indoor aerial (if you are in a strong signal area) or an external aerial if you want decent reception.

The UK FREEVIEW boxes do work here as the standard is universal across Europe (unlike the old TV standard). You can buy FREEVIEW (TDT) boxes here for around 35 euros for the cheapest or around 50 euros for a better quality unit.

FREESAT is received by satellite and from a dish and you can get UK channels. A 1.2M dish is recommended however you can get away with a 1M dish if you are prepared to suffer breakup of the signal on some channels during the winter and in bad weather. FREESAT boxes are available in some Electrodomesticos and Bauhaus have them.  I tried one of the cheap ones once but it suffered badly from locking up and eventually locked up and would not reset so best avoided!

I supply FREEVIEW (TDT) and FREESAT(Satellite)boxes and also install TV aerials and Satellite dishes. The FREESAT boxes I sell are usually 70 euros and are of decent quality.

Nigel