This is a questoin I get asked a lot of times....

If you connect a Spanish analogue TV aerial into an English tv the TV may not work.

This is because British TV sets operating on the British system (PAL-1) where are Spain uses the PAL- BG standard.
This meanas that you may get picture but not sound. However, some newer TVs do have pan European settings thought and should work.

Any device, like a satellite receiver or a TDT (Spanish Freeview!) box, you buy in Spain and connect to your TV via the SCART / EURO connectors will work.

Uk TVs with inbuilt Freeview digital TV tuners may work with Spanish digital tv service (TDT). TDT is similar to the UK freeview service, but certain options (ie change sound / all channels) may not work.

For example UK Freeview branded boxes mainly use audio "tags" for the different language tracks for the UK only....these are generally English, Welsh and Gealic. If you use a UK Freeview box in Spain, and are watching a Spanish TV station that uses the audio "tag" ESP, or CAT, the UK Freeview box may not recoginise it and therefore may not output any audio. only a few (SET and Disney) use the tag "English" as an alternate audio flag. A seperate TDT receiver will overcome this issue.

See this page for more information
Freeview and TDT In Spain

Hope this helps