Salisbury plain. Use shrewton for directions. There is no site postcode as it is a genuine live training area. Directions will be published at a later date with the right road and the right tank junction
(They are available if you search about for the previous games)
For coming from London you want m3, a303 up to about Stonehenge and you're pretty much there
(Just for reference - sat navs may have a problem next year as they have just shutdown one of the roads at Stonehenge and seriously messed up a303 traffic.
The Stonehenge stretch of the a303 has always been a bottleneck but the council have seriously screwed up and buried their head in the sand saying its the highways agencies fault for not making the stretch into a dual carriage way