The shortest five pin cylinder lock is 30mm each side (a six pin lock would be even longer). On a narrow gate this leaves too much of the cylinder protruding making it easy for thieves to apply a wrench and snap the lock.
On the 5th of this month I wrote about the Snapsafe replacement lock cylinder but unfortunately have not been able to find any here in Spain. In any case the Snapsafe is only designed to snap on one side which is fine for a solid door but not ideal for the type of gates we are looking to protect.
The sinple solution is to fit cylinder protectors. The one in the picture is from Pepe Lorente whose place is just up the road from the Cepsa garage. As you can see, it's narrow enough to fit on a gate and is deep enough to leave just a couple of millimetres of the cylinder showing.
You can fit them with self tapping screws by drilling two holes like I have in this picture or better still have them welded on to the gate.