If you pause the video at 0:06 you'll see the sign showing two lanes - the van should've stayed in lane a bit longer before moving over (blindspot) but I'm assuming the van driver was impatient and decided to undertake the lorry
At least you know the brakes work 
personally I would've held back just incase the lorry wanted to move to the nearside to let things overtake, especially with it being uphill.
Pretty stupid layout really, they'd be better making it a giveaway just after the crossing or making it a solid white line all the way up.
When I learnt to drive - probably long before many of the current forum members were even born
(it was in the 1970’s, and petrol was around 80p a gallon!) - one of the most valuable lessons my driving instructor taught me was to treat all other drivers as idiots, always assume they might do something unpredictable and stupid, and leave them sufficient space for their stupidity.
Those were very wise words that are probably even more appropriate today, considering the significantly higher traffic volume on the roads now compared to the 1970’s. I still treat all other drivers as idiots to this day - no offence to forum members! In doing so, it has saved me (and my car) from some potential unpleasant situations on a number of occasions over the years.
Agree that the road layout seen in the video clip could be better. IMHO that van driver is a good example of why other drivers should be treated as idiots.........
