[QUOTE=Safeone;25226]Thats the picture I was thinking of, where is it from ?

I now have an image of someone walking round in circles unscrewing a Chubb Trident from its base bolt :-) !!!![/QUOTE

Hello Safeone.
I can't find where I first showed this. It was taken in the Tann test facility in Borehamwood in the late 80's. The anchoring followed the Rawlbolt instructions to the letter including using a puffer to blow any spoil from the drilled hole.
I'm the boy in blue. The lever is a bending 30mm pinch bar.
Chubby is dead right when he gives the solution to this by chamfering the underside of the carriages and centres.