T i m wrote:

So, for those that have used these Robinson screws / bits .. what are
the pro's n con's please? They do look like a good idea and in this
country (where they aren't commonly used) could provide a bit of mild
security on 'publically' accessable things?

You can put a Robinson screw on the bit in an electric drill,
hold that horizontally and the screw won't fall off as you screw
it in. And the bit never slips and messes up the screw head.