There was a public consultation, which was widely publicised including in this Forum: RE: Public Consultation: PAS 63100 Electrical installations – Protection against fire of battery energy storage systems for use in dwellings – Specification
I'll cover the battery standards first. This is (As We fix Solar is concerned) interesting and will perhaps cause some debate (apologies for that, but here goes ...).
Quite simply, the lack of a standard for domestic lithium batteries causes their selection to be a "non-standard approach" as far as BS 7671 is concerned. Some more standardization work is needed here ... whether that's development of a domestic battery standard, or a way of making it possible to recognize industrial lithium batteries used outside the industrial sector is of course open to question.
Similarly, if you are quoting UL or other standards not aligned with IEC standards, Reg 511.2 again effectively requires some form of statement from the designer or installer as to the safety being "no less safe than BS 7671".
Perhaps less controversial is enclosures. The standards for battery assemblies/installations in 6.2.1 of PAS 63100 are not those simply of the "enclosure", but cover installation or assembly of "batteries in enclosures". The ones quoted are assembly or installation standards for batteries in enclosures (or in the case of BS EN IEC 62485 series, in commercial/industrial situations this could also be a battery room). This would not preclude the use of BS EN 62208 enclosures ... but it would be up tot he designer of the installation to check ventilation and protection requirements in selecting an appropriate enclosure. Referencing particular BS EN IEC 62485 series is not new ... it's been referenced in the IET CoP for EESS for some time (perhaps overlooked?). BS EN IEC 62485-5 had not been published when the 2nd Edition was finalized, but I am quite certain we will see that standard referenced in the 3rd Edition which will be available very soon.