I find it hard to believe that even you think that such a degree of difference can be explained by the CPC redundancy, which appears to be the only real 'safety advantage' of ring finals - so it seems unlikely that the difference has got anything to do with our use of ring finals. Certainly if you look over the period of our use of ring finals, aren't the more important factors likely to be things like our use of fused, earthed and non-reversible plugs, and shuttered sockets?I still can't find it, but there's a document somewhere (HSE? Eurostat? ILO?) that points out that the UK has about half the rate of "electrical incidents" of the next lowest country in Europe. All (as far as I know) of those other countries use radials, so even allowing for statistical errors, we seem to be doing something right.
Kind Regards, John