you cannot get UK TV in spain on a freeview box, as freeview is not broadcast in spain. you can get the spanish equivient of freeview called tdt...30ish spanish digital tv channels - no uk channels - but in some cases you can change the languages from spanish into english.
for uk tv channels you will either need a satellite dish (for bbcs and itv a biggie like 1.8, for nonbbcs and itvs a 80cm to 1m dish should do) and a satellite receiver, and, if you want to, a sky subscription for the pay tv channels.
you can also go for one of the rebroadcasters - who reboradcast channels for amonthly payment using a little mesh aerial on your roof - many of the channels are available for free on other platforms like satellite and TDT!
you can also go for the spansi Digital+ service - its the spanish version of Sky. mny channels on sky are on D+, like discovery and movie channels, but there areno main UK TV channels.
for more info on UK TV in spain have a look here
http://www.satandpcguy.com/forum/sticky-freeview-freesat-tv-freesatfromsky-sky-tv-uktv-240109-t63.html
or look at the many other threads in this forum...