I agree with the importance of good training however I am not sure I see the level of danger that you are suggesting.

Most countries other than the UK allow power sockets in bathrooms. There doesn't appear to be a higher accident level in these lands.

Many countries have far lower electrical installation standards. On one Chinese building site I complained about a twisted and taped joint in a 400V 3phase cable being out in the rain. They considered this to be resolved by putting an upturned plastic bucket over it.

Solar panels on roofs have two intrinsic risks, working at height, and they can't be switched off, you just have to wait for it to get dark. I would suggest that injurys due to falls from height are much more common than electrical accidents.

What are you considering to be dangerous and are there any accident statistics?

Indeed working on a pitched roof is a self evident hazard.  Joe public doesnt always appreciate the nature of continuous high current from a panel - its not obvious, furthermore you cant test for a "live" circuit"  like using a neon screwdriver, you must have a special dc clamp meter and these have only been commonly available in the last few years (ca£60 for reliable meter - how do you test it is working? , a neon you stick it in the nearest mains socket).

Then you come downstream to the installation wiring and switchgear/fuse protection - this is where it all become a can of worms.  Joe Public will generally not have an appreciation of the risks involved there after - I wont labour that point here - it should be understood by IET Members  although without a particular study of this area, the risks may not be truly appreciated.  Im a highly trained EE rtd  and have studied this for over a year as I was chastened to discover how little I appreciated the problems of ELV high current dc.  I was never involved in Power Systems Engineering, nor did I practice at electrician level - 3 phase scared me - and still does.

A glaring example of regs patchy treatment is that a Firemans Switch is not mandatory. for solar systems.

Note that whatever system is cobbled together by amateur treatment has to run 24/7 unattended and have emergency shutdown or routine operation by untrained persons.

We take for granted the purpose and operation of our domestic consumer board and its MCBs.  A solar system distribution up to the inverter and its  input to household supply and maybe a grid export metering and/or batteries.

Most amateurs Ive seen on YT  Vids just string it all together somehow  - never a hint on an SLD.  or system safety analysis

This is made all the worse by the tidal wave of Cheap Charlie switches, fuses, breakers, inverters etc comprising the installation

No consideration of smoke detectors AFFD's, heat detection , temperature logging

And you ask why I think the risks are not being taken seriously in UK?  We dont have trained inspectors (LGA employed not subcontracted out)  who issue a PTO - permit to operate.  When the amateur gets it wrong it can burn his house down.  There are countless examples on YT.

A couple of quick points:

What are you expecting the firemans switch to do? What can it isolate, what will it leave live?

Are there countless examples on YT of what you consider incorect or countless examples of houses burning down?

A couple of quick points:

What are you expecting the firemans switch to do? What can it isolate, what will it leave live?

Are there countless examples on YT of what you consider incorect or countless examples of houses burning down?

Here is the conventional Firemans switch often seen on shop fronts

https://www.youtube.com/watch?v=GZD7hdXP0oI

Unfortunately its a 3ph blade switch for ac only.  But you can see the purpose

I havent seen an equivalent suitable for dc use yet  - try browsing and let us know.

Here is an example of a huge scandal in OZ when a mandatory mcb was installed on Solar systems.  In OZ they have a national sponsored push to get every roof retro-fitted with panels

https://www.youtube.com/watch?v=EJC6wKir_Lo&t=9s

A test to show what happened - there were numerous fires before their Regs were hastily changed and this particular device was outlawed.  There are numerous Cheap Charlie MCBs offering dc disconnection as well as 1/4 turn rotaries

I spent over a year researching these horror stories, there are hundreds of YT examples and some from Companies who should have known better.

Some enlightening reading

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/630641/fire-solar-pv-systems-frs-recommendations.pdf

Conclusions

Recommendations to improve the safety of firefighters responding to fire incidents on buildings where PV
is present are summarised:
 Information on appropriate emergency response methods of making PV systems safe – requires
further research.
 Ability to identify the presence of a PV system early on in firefighting operations – this could be
improved through training and through PV installers use of the ‘Solar PV on roof’ label as
required by MCS [9].
 Revision of NOG information – in discussion between CFOA and BRE Fire & Safety Team.
 Consistency of SOPs for PV across all UK FRSs – preferably using new NOG information.
 Provision of training to fire crews in the following:
o Basic understanding and recognition of the PV system components and labels - in order
to quickly identify the presence of a PV system, assist with risk assessments and to
provide more detailed information to fire investigators and during debriefs.
o Details of the hazards that a PV system may introduce to a fire incident – including
associated hazards such as potential to electrify other conductive objects.
o Safe isolation procedures – including an understanding of what parts of the system
should still be considered live.Other approaches that can be taken to deenergise systems
and the risks that these could pose to fire crews.

And here is a source that will show where the USA and its revered UL  are going with the technology

iaeimagazine.org/.../

I will repeat my question, what does the Fireman's switch isolate and what does it leave live? They were originally used for high voltage neon signs on shop fronts and then I believe for electric petrol pumps (may be wrong). If you break the circuit from the solar panels to the inverter the panels and the wiring down to the switch are alive. You also need a switch capable of breaking a few hundred volts DC. A shorting switch might be better?

Similar problems exist with EVs. The HV cables are required to be in defined places that are in the emergency services documentation. They must also be orange and have a grounded screen. These carry similar voltages and higher currents than PV systems.

More house fires are caused by other things than solar panels, probably smoking and cooking are the main causes. Do some Pareto deal with the 20% of the causes that result in 80% of the problems.