My daughters' school teaches both French and German, but you only learn one of the languages for the first two years. After that if you are in the top set for one of the languages you are offered the opertunity to take up the second language - but it means staying for an extra 2 hours one night a week. So far daughter 1 is doing this, but as the nights get darker I can see her commitment fading, as she then has to catch a regular bus home rather than a dedicated school bus, so longer walk at both ends. I wish they could fit it in better if they are to keep the kids interested in languages.
I think other schools nearby also teach spanish.
Its probably a good point about A-level's - I know some teachers who prefer teaching A-levels or at least teaching A-level as well as GCSE, but only a small number of local schools have 6th forms.