Turn to your right and walk 30m or 40 steps forward towards the lift lobby. The lifts will be on your left

Take any one of these lifts down to the ground floor

Exit the lift and walk to your left. Turn left again immediately 

This is the doorway into the west wing

Walk through the doorway and walk 65m or about 86 steps forward to the end of the passage

Turn left and walk 118m or about 155 steps forward along this passage

The main west wing reception will be straight ahead of you