I understand that all building contractors are off site sometime in May and from then on the site has controlled access. From what I've heard the secret grapefruit extraction machines are then being installed.
I don't know what Doc Logic has heard ( I presume something similar ) but I happened to know one of the contractors working on site.
I don't remember the exact post but I think it was from Jack or Longfellow95 that mentioned plans for installation of production equipment at Sawston in May and that all non related parties involved in other construction would be kept off of the property during this time. I'll try to go back and find it. Best wishes.