In 1951 on the way to Southampton to join the liner that was to convey me and other airmen of Draft 2128 to the Rhodesia Air Training Group, I had time to spare at Waterloo and visited the the Festival of Britain exhibition on the site adjacent to Waterloo station, the date from my diary shows it was Wednesday 18th July 1951.
The aviation gallery in the Tranport Hall had a Schneider Trophy Supermarine S.6 seaplane and DH88 Comet 1930's racer on display as shown in the photo below.
Not sure whether the Schneider Trophy Supermarine S.6 was an original aircraft or replica, but it certainly drew the crowds.
Would the one I saw in 1951 be the one going on show at Calshot?