Chevvron,
Always a Sapper is correct. UK RAF barriers were usually remote operated UP or Down and, I do remember a series of "barrier incidents" to do with possible unreliable operation. Likewise, most RAF RHAG were manually raised on grommets. Yes, the RHAG cable was required to be tensioned whether UP or DOWN. If the RHAG cable could not be tensioned, it needed to be removed. Occasionally, I have landed "beyond the cable" when the trampling criteria could not be met.
BTW, the NWS low light on Tornado shows if the NWS is functioning correctly. I made several RHAG engagements and I was very grateful for their availability. Never needed the Barrier but, again, thanks to everyone who maintained and operated this kit for us!
OAP