Have just looked in my leons owners manual and
YES you could have TCS without ESP it works along side your ABS, however it dose state it can be turned on or off buy pushing the button on the console.
Reasons you my wish to turn off is
WITH COMPECT TEMPORARY SPARE WHEEL
WHEN USING SNOW CHAINS
WHEN DRIVING IN DEEP SNON
WHEN THE VEHICLE IS BOGGED-DOWN, TO FREE IT BY ROCKING
Would think this is the same for a
Ibiza I should have looked in the manual in the first place.