That expalins why so many farmers don`t have licenses.
As for EU rules, the Spanish was fined in or around 2004 for ignoring EU regulations regarding driving rules.
The Spanish have under Royal Decree declared that the clause in allowing local regulations to over rule EU Directives is to be extended.
Or something to that effect.
Its difficult to get any correct written in stone explination, I guess there earning enough in fines.
All the info on the net states that EU licenses have to follow Spanish local laws to be valid, problem is that a UK license does not require a medical and is valid longer than 10 yrs.
Whereas a Spanish license becomes invalid if no medical and older than 10 yrs, so by Spanish rules a UK license is both valid and invalid.
Unless your a Guardia Traffico whos been informed to ticket all UK license holders resident in Spain.
A lot of sites state that a Non Spaniard has to gain a Spanish no later than 6 months of becoming resident within Spain.
I guess its just easier to get a Spanish license, as they say when in Rome.