Crab,don’t know whether this was passed along thru Westland, but the initial SH3A ( first 61 model ) did not have collective vs longitudinal limiting and the first USN ships had progressed into training the first USN pilots, when after one of our guys, having just been briefed by Bob Decker, the Ch Pilot, on being careful about this ( EOL ), went out and “showed” a USN pilot how to clip the top of the tail drive shaft cover and shaft. That little event resulted in the mixer/limiter, and it worked OK and all since benefitted. Before I signed on.
You may have seen pictures of the original UH-60 prototype with the low main rotor. That ship had both a forward and aft limiter. After we raised the main rotor six months into the test program, we left those limiters in, and were able to do the 12 degree and 15 degree slopes per the Army requirement, so they remain in place today.