The infopack says "If possible we would recommend parking your car and bringing your parts through the main entrance to avoid you
having to get loading passes."

And also "Once unloaded all cars will need to be taken back to the main car parks. Last year there was congestion to get access to this loading door so if possible we advise parking in the car park and bringing your goods through the main entrance."

So bring your hiking boots! I tried a Google street view drive-by, which didn't help much as it doesn't cover the private roads.