As an update, the bolt with part number 68222835AA is not the correct bolt for the lower headlight mounting through the spacer (68222836AA). This bolt is too short and is in fact the bolt used for the upper headlight fixing. The bolt that is required to secure the headlight through the spacer needs to be approximately 50 mm in length. However, I'm unsure of the part number for this?
In addition, the u nut with part number 6105242AA is approximately 20 mm in width. Although this fits and may be used to secure the headlight through the spacer, it's a little too wide and it pushes on the the spacer lugs. The original u nut is approximately 16 mm in width. Both u nuts are approximately 25 mm in length which is fine. It would be good to find a u nut of similar width to the original.