Does not work with Xenons.
You have to use VCDS and goto the following.
Central electric ---> Coding ---> long code helper
Byte 11 select it
A box below will now appear.
A tick box next to 'Daytime running lights via low beam' will be ticked, click it to untick it. click back, click 'do it'.
DRL as xenons will now be turned off.