Do you do long term rentals on cars ?
Normally one month at a time but it can be longer, use the website and it will show you. Probably a maximum of 3 months unless you make another booking of course.
We are in Spain for a long term, so maybe I could rent the car twice for 3 months.
Yes, but experiment with the website as it will stop showing you car photos when you reach the maximum period and try a few different suppliers.