Here you go, mine:
https://imgur.com/a/Yilnm0f
One on the top row only turns on when ignitionon is on, bottom row is always powered on (my Garmin has a parking recording mode).
If none of these are free on yours, try another. You'll need to test the voltages, some with iginition off will drop to 5V and ignition on 12V so do not use these, some others fuse sockets your CAN Bus may get triggered so the ECU is turned on, meaning you'll have a flat battery if you do not drive it for a few days, so make sure the empty slot isn't realted to the engine at all.
https://fuse-box.info/seat/seat-ibiza-mk4-6j-2008-2015-fuses