> The system is allowed it to be done is devised and run by the civil service,
The system that allowed it to be done is supposedly controlled by civil servants. But they rely on expert companies to help devise the standards. But experts in something detailed and specific like construction cladding tend to work for the cladding manufacturers themselves. So you end up with the industry marking its own homework. After a couple of years, the civil servants move on and there is no longer any expertise with which say 'hold on, you can't do that'.
A similar example has occurred over the years with abattoir rules. One particular rule requires a vet to be present on premises at all times during slaughtering. This is an utterly pointless waste of time for a skilled vet but has the benefit of being very expensive - so large abattoirs running at industrial scales can absorb the costs and small, family-run abattoirs have all been forced to close. These rules were promoted by the large operators ostensibly on grounds of animal health and it was purely coincidental that it eliminated cheaper competitors.
 And animal health is actually worse because the livestock have to travel a much longer distance from the farm to the abattoir instead of a short distance to a local place that previously may have only operated part time.