I fear the one that made me cut out the coupon and start the process was one of the "Deserved it" series of circa early 1963 with, I think, a very moody Vulcan-by-night picture. Terribly effective at the time, I recall, but sometime later, having had a quick look at the interior of same on a Nav School visit to Finningley, I decided that I was probably cut out for the more expansive interiors of the AT Force .... and never looked back. But I repeat, it was that damned ad that made me do it! 50 years on, no regrets at all.