I need to cut back an established Green Beech hedge to 900mm to comply
with some Planning Regulations, but am worried that this may be too
severe, and the Hedge may not grow back.

The current hedge is around 2.5m high and 1.5m wide, and has been
established for many years. My alternative would be to completely
remove the existing hedge and re-plant with fresh Bare-rooted stock.

Any advice would be appreciated.