Dave Plowman wrote:

But if the rawlbolt pulls out of its hole enough to hit the plate it
should then expand fully when tightened. Which will at least give some
additional strength.

I'll try that, thanks.

Incidentally, in the absence of a torque wrench how aggressive should I be
in tightening the bolts? Will I damage them or compromise their grip if I
simply do them up as tightly as I can?