Talking Pictures TV had an episode of the Look At Life short documentary series about "muscle men" which included a couple of minutes of Szakacs-Stein. I believe it was from the 21 September 1960 show at the Royal Albert Hall, so is very likely the earliest colour footage of UK wrestling that still survives.
Unfortunately it doesn't look like any repeat showings are scheduled and I suspect it wouldn't last long on YouTube before it was taken down.
I posted the youtube link recently