I know Jaen province pretty well. You may have some success buying something in Jaen city, which has quite a big student population. Otherwise, you should forget it. Jaen has one of the highest unemployment rates in Spain at around 40%. So even if you could find tenants, you may find problems getting paid each month.
I know a lot of people from Jaen and they lived with their parents until they got married and then they bought their own place. The only people I know that rented were the ones that had to move from their towns/villages to go to uni in Jaen city.
Why would you even think about buying property in Spain when you can get such good yields in the UK (at least up north) ?