My nephew used to Captain J41s (not in the UK) and they usually parked on the apron in such a way as to be able to go forward.
If I recall correctly, if a powerback was required the formula was:
- Open the throttles a touch
- When you have travelled 2/3 of the way - close the throttles
- Let her drift to a stop then apply brakes and set the pitch
- DO NOT touch the brakes when she is rolling as she will almost certainly sit on 'her backside' without warning and VERY quickly!
Generally as I have ever seen it done (in tail mounted jet engine aircraft). Taxi forward, apply reverse thrust as required to to taxi backwards, advance thrust and NEVER apply the breaks until you have achieved forward movement. Not sure if it is much different with turboprop a/c.