Ian
As you say you were at Grove Park in the 1970's, I joined BR in 1979, what we were allowed to do then and what we are allowed to do now are totally different things, you describe what is known as a propelling move, but, in recent times this has been all but banned and any move must be made with the driver in the leading cab. the only exception would be where a 2nd driver is available to drive from the leading cab.
Ian