Hi,
While I was at Uni I did a 6 month spell on shop-floor at Brough in '68 or '69 and saw the low-level photos on the notice board. They were doing some low level flow visualisation work with tufts and the easiest way to get the photos was from the top of the water tower. Pilot was Dereck aka Block Whitehead.
I went to a RAeS lecture given by him and heard some of the tales including a refuelling test flight with Buccaneer buddy refuelling another Bucc. Block was lead and he gradually drifted down to below 100' and the guy in back had to get lower or break-off. This would have been one-up to Block so they continued on down until the receiver was just above the hedges!