When learning the British way of helicopter flying years ago after learning the US Army way.....one of the biggest differences I saw in the two schools of thought involved confined area takeoffs.
Each system seemed to mirror one another in the method for doing a "towering" takeoff but differed greatly in the decision to use that particular method.
The US Army, in its infinite wisdom, taught us three techniques for doing confined area takeoffs....those being the "towering takeoff", the "ETL" method, and the third being a combination of the two where the profile had you moving forward and up but below ETL to clear your barriers as a safe height (same height as used in the British/American Towering Takeoff).
Bill Barrell, a well known Bristow Instructor with tons of experience and I experimented with the three methods in one of the overpowered Bell 47's assigned to the Bristow School at Redhill.
Our exercise seemed to show the power required for the US Army Foreward and Up profile and the Towering Takeoff required the same amount of power with the only difference being the forward speed as one crossed over the near barriers. The question that remains is whether the greater speed across the ground using the Towering takeoff vice the slower speed using the US Army takeoff presented the less desirable situation. The Army method meant you were giving up room in front of you while still below the barriers but you had a slower rate of closure.
As usual in helicopter flying....sometimes there might be more than one correct answer to the question in my view.