4th gear, across the hatch lines and straight up the arse of whatever is in the way in the fast lane. 
My mate does that haha. used to make me slightly nervous.,...but now im used to it.
In regards to the thread. I really cant fault the van driver at all. You came onto the main road, from the slip-way, and was constantly in his blind-spot. he probably did everything correctly in terms of checking his mirror, indicating and proceding to move into the 'turning off lane' however because you merged onto the road at a speed greater than that of the flowing traffic, id say puts you at fault for intentionally sitting in a place where you cannot be seen at his mirrors, and should he have carried on, not wanting to change lanes, would have undertook the van driver.
Just my 2cents at end of day though....luckily no casualties r damage caused...just experience gathered!