After (none too careful) research, the only slight window of hope is via BAFE or similar.
From one of the multitude of RR(FS)O guides
"Third-party certification schemes for fire
protection products and related services are an
effective means of providing the fullest possible
assurances, offering a level of quality, reliability
and safety that non-certificated products may
lack. This does not mean goods and services
that are not third-party approved are less
reliable, but there is no obvious way in which
this can be demonstrated.
Third-party quality assurance can offer comfort
both as a means of satisfying you that goods
and services you have purchased are fit for
purpose, and as a means of demonstrating that
you have complied with the law."
I presume when our marrer from Clapham stands up in court after his DHSS hostel has become charcoal, he will have to prove "best practice" in his fire safety activities. Checking them himself (and therefore certificating himself) after the above has been penned, may not be seen as such by the higher beakage.
It's a thin ice activity but I'm sure some will go for it and then throw blame at the manufacturer when it all goes wrong because the man from Claphams playful nephew set on off and left it half full in situ without telling him and that was never mentioned in the (self) service manual and neither was the fact that Mija pressure gauges (and all their ilk) stick on 'full' with alarming frequency and this kit has two of 'em.