We`ll if your near Malaga city, there`s a donor bus parked up outside Corte Ingles near Avenida Alameda every weeks.
Although you have to have lived in Spain for 5 yrs (I think, but not sure).
I think there is still a ban on Brits donating due to the Mad Cow incidents (again not sure).
The bus used to visit tourist beeches, that seems to have stopped, you only needed a short examination, then wham out comes the Sangre.
The CRTS runs short in malaga region every year, if your in the region just pop along to either the mobile bus or the Civil Hospital in Malaga city.
or contact
http://www.donantesmalaga.org/