Scott, how can H&S say no to something? This design looks a bit dangerous, you can not build it?
They might of said, your not doing it unless you do this, this, and this to prove its safe, which Merlin did not want to waste time and money going through.
Knowing Dave's and the teams contacts, I am assuming this rumour has come from someone senior at Towers, so there probably is some truth to it, but I doubt very much H&S stopped Towers.
Fair enough, if the lap bars had been tested, and the dummy's were getting thrown off the ride, and all over the place, but for it to have not even be tested in the UK, and for it to be the manufactures standard choice of restraint, I do not believe that H&S stopped Towers from using Lap bars.
Until the source of the rumours is made public, or Merlin/Towers/Gerstlauer make a public statement the real reason will never be fully known, and it is just fun for us to speculate about what the real reason was
Ian