Hi Prof
There would appear to be several issues here
1. The issue of allowing only two years to apply the new standard
2. The rejection of the 'safety by statistics' approach
3. The apparent preference for a BS over Statutory Regulation
4. Whilst an employer might carry out all the work that was required under legislation, there is an extra requirement in that if further work is identified either by BS or Risk Assessment, it is incumbent on the employer to carry out that work.
In regard to your question, like fire, H & S requires an employer to keep up to date with developments and so both in the case of installation and the date of the incident any investigation would seek to identify if this was the case, and, as you say, no doubt the legal eagles
davo