Many people are getting a message on their SKY boxes informing them of the Sky card change.  If you have a Sky subscription then Sky will send you a new white card to your registered address (which will be one in the UK).

If you only have the free channels then you either need to buy a new card or contact Sky for a replacement.  You can check what you need to do on their website here:
https://mysky.sky.com/replacecard/index.jsp

If you don't replace your card then you will lose some, but not all, channels.
DO NOT ring Sky from Spain unless you have a phone service that presents a UK CLID as you are not allowed to receive UK TV in Spain.

Tha alternative, if you don't want to buy a new card or contact Sky and don't want to lose channels is to change to a Freesat box.  At the moment FIVE USA, FIVE USA +1, FIVER and FIVER +1 are not on freesat but may come soon. Basic freesat boxes cost between 70 and 100 euros and there are also versions that have both Satellite and Terrestrial TV option (for those who want to view Spanish terrestrial TV).  There are also freesat boxes that have recording capability - as per the Sky+ boxes.

Nigel