The zone shown on the map (see link below) has a legally-enforceable width restriction (up to 6’6″) within the dotted area. Unless the vehicle has a destination within the area shown (eg tractors, lorries delivering to sites within the zone, removal lorries etc), this area is now banned for shortcuts. This should help to reduce the amount of mis-directed traffic and also stop  trucks using the road through Monxton as a rat-run between the A303 and A343 or Grateley to Andover.
Width Restriction Map