To be fair Chris, this 'post fire' audit procedure has only really be developed by the LFB since the FSO was introduced to take into account the enforcement status with comes with the Order. A fire is seen to be merely a trigger for such audits which are carried out in addition to programmed audits.
Yes in the past a FS IO would often (if not always) attend after a serious fire. But now we attend - unannouced- after EVERY fire - Whatever the cause and whatever the size - Even if in residential property if we suspect that premise has common parts (ie flats).
In addition to attending 'real' fires, I have been to audits originating from smoking toast setting off the AFD and subsequently being record as a fire for the sake of records (FDR1) and following an overheated lift and the good old favourite, an over heated choke on a strip light fitting. All get an audit and many audits pick up difficulties.
So although I accept that post fire audits look like a limp & retrospective 'stable door policy', there is real evidence to suggest than many (but not all) fires occur as a failing in management or systems which benefit from an immediate audit. Also in the case of arson, many premises targetted will receive a repeat visit by the vandal, so again, early intervention by the Brigade can be useful.
Lastly, although the company involved here were perhaps, as you put it: 'in breach of the regs before the fire too', it is not the responsibility or fault of the local FRS if that situation occurs. That's clearly down to the resp person, and post fire visits will often discover any disregard for the regs and act accordingly.