We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember The Other Mike
saying something like:

Maybe these?

http://www.rawlplug.co.uk/index.php?...=92&Itemi d=0

That's the ones. My local stockist only had the Torx-head versions, but
that was no problem. The first one went in so easily I thought it
couldn't be a good fixing and would pull out, but no amount of pulling
and tugging on it would shift it.
For 7.5mm the drill hole is 6mm, information which was lacking in the
stockist's shop.