Mogwi, I wonder if Westland (or whatever they're called now) might help you. Any Design Authority is always keen to understand the effect of damage and effectiveness of BDR. I recall them being very impressed with one particular Sea King from 1982. It was left as it was many years later during an upgrade, but the changes had to be recorded in the drawings as a modification set in the nose avionics bay had to be a special order.