I stayed for a third year at college.
First year - I chose to do French, Spanish, History and Law, but I didn't like History and Law at all, so I dropped them half-way through the year, and completed the year with just AS French and AS Spanish.
Second year - I took up AS Classics, so finished the year with AS Classics, A2 French, and A2 Spanish
Third year - I decided I wanted to improve my French grade (I had got a C first time round for A2), so I retook A2 French, and also did A2 Classics, and GCSE Italian.
So I ended up with A-levels in French, Classics, and Spanish.
There was no problem with me going to uni - my having been at college for 3 years didn't even come up!