Do the RAC still go in for the two-way stretch? Maybe not since the advent of bonedomes. In the 70s, the Larkspur headset sat best on the head if the beret was pulled down on both sides and the badge in the middle.
I once attended a course at Warminster along with a number of others. There was myself and one from 3rd Bn RGJ, 2 from 2nd Bn 2 from 1st Bn and we all wore our badges in different positions. We were able to convince the Ds that it was regimental tradition that the badges were worn where they were. Luckily, since he was one of the pink hatted types - who owe their greatest and best known battle honour to a Greenjacket battalion - and not the brightest bulb in the chandelier, this nonsense was never queried.