Vauxhall ASTRA Owner's Manual page 271

270 Self-help, vehicle care
Dipped beam
1. Replace bulb through the opening in the
front wheel arch: turn appropriate wheel
to gain access, release catch and
remove cover, see page 269.
2. Remove headlight protective cover.
3. Rotate left bulb holder and disengage. 4. Remove the bulb holder with bulb from
the reflector.