I joined 637VGS as a Staff Cadet in 1971 and had the pleasure of meeting David Assinder, who had been in the Glider Regiment and ended up being seconded to the Glider Trials Unit.
He told me the story of the very early 'snatch' launches that were carried out using a Wellington. The first launch took the nose off the glider (cannot remember what type). The next was using, with a reinforced nose structure and a minimum stretch rope - the result being the fuselage stretched more than the elevator control runs!