Welcome to the forum Jomo.

You don't state the year of your GTI as with 2011 and later you can't disable the DRLs manually as shown here you need someone with VAG-COM\VCDS.
What they are saying on here is.
DRLs OFF1) Headlight switch to OFF (0),
2) Select Left indicator while
3) Simultaneously pull the indicator stalk back towards you to flash the lights while
4) Turning ignition ON on for a couple seconds - until you hear the DING.
DRLs are now OFF.
DRLs ON1) Headlight switch to OFF (0),
2) Select Right indicator while
3) Simultaneously pull the indicator stalk back towards you to flash the lights while
4) Turning ignition ON on for a couple seconds - until you hear the DING.
DRLs are now ON