O-D - Practice assymetric
I think the problem in the early fifties was that the Air Staff, who had to make the decisions about training were all of the piston engine era. The reliability of jet engines hadn't registered with them so engine out situations were at the forefront of jet training so most of the practise asymmetric accidents were in flying training. The operational squadrons flying Meteors didn't have the same problem because generally their asymmetric flying was, very infrequently, for real.
By the sixties this attitude had changed as I know from my own flying training. During the Provost T1 stage a 'Fanstop' was quite normal just after takeoff. On Vampires I never had the throttle pulled on me just after take off because there was no need and anyway, if all else failed it was 'If in Doubt, Bang Out'.