Assuming an asymmetric, high intensity cut-off pattern headlight:
Eg 1. A vehicle with a manufacturers dip beam angle of 1.3%, has a dip beam that will sit 39mm below the horizontal
centre-line of the headlight when measured on a light board set up 3m away from the front of that headlight.
Eg 2. A vehicle that doesnt have a manufacturers specification for the dip beam, has a vertical centre height of 765mm. Provided that, at 3m from the front of that headlight, the dip beam falls within a band 30-45mm below the horizontal centre line of that headlight when viewed on the lightboard, it will pass its WOF inspection.