In the late 80's I attended an evening lecture given by the late Roland Beamont in Swindon on the subject of Canberra flight testing.
He showed one photo of himself displaying a Canberra at a Farnborough SBAC show with the aircraft in a turn, close to the ground. He told us that RAE technicians had analysed the photo and concluded that the lower wingtip was four feet off the surface.