You need a DS1 xenon bulb www.autobulbsdirect.co.uk/replacement-d1s-xenon-hid-bulbs/To replace it you need to remove the headlight and in order to do that, remover the bumper.
Best of luck sorting it HF0, hope it is less hassle than it sounds.If I ever have this issue, do you need to use a Vag.com to reset or align the headlight, or just to clear the warning light on the dash?