Morning matelot1965
So, presume the bit in the guidance you are referring to is
"5.6.5 Where it is not practicable to provide this degree of physical separation of a vehicle charging area within a building as indicated in paragraph 5.6.3 (and also outside the premises), no charging should be undertaken within 10m of any combustible materials: be they waste materials, stock or combustible elements of the structure. Similarly, no charging should be undertaken within 15m of hazardous installations such as transformers, flammable liquid stores and liquefied petroleum gas tanks."
The document was published in 2021 and might not have been out when your charging points were installed, but in any case, is guidance rather than a prescriptive requirement of DSEAR or other legislation and will be inherently erring on the conservative side - as example, it doesn't set different separation distances depending on the scale of "hazardous installations" and doesn't distinguish between an LPG tank that has an intumescent coating +++ against one that does not have such additional protection.
Suggest your starting point is to establish what authoritative (or semi-authoritative) guidance was in place when the charging points were being procured and identify what was written in to the specification for the installation of those charging points.
So, if the specification said words to the effect of "comply in full with .RISCA RC59", then may be you go back to the installer and tell them to comply with Contract - but that is somewhat subject to whether a Contract Administrator has signed off the Contract as being successfully completed to specification.
Then you look at who the Contract Administrator was - if within the organisation, somewhat stuffed, but if you have bought in that service, then may be an action against the CA.
Part of this might depend on the handover documentation provided with the charging points. Does this warrant that all is fine and dandy?
Now assuming that reverting to issues surrounding the procurement is not going to work, you then need to decide what to do, if anything, to comply with the relevant legislation. That probably means getting in a specialist to do a detailed DSEAR assessment to explain why you can depart from the details of the RISCA guidance or do whatever to mitigate aspects where the installation departs from that guidance.
.....and that will have to look at multiple variables - e.g. for the LPG tank(s) - how many, what capacity, how loaded (and, if ever, unloaded), methods of coupling, actual distance from the charging points (and other potential sources of ignition) - so, if say 14m from the nearest charging point it's a fairly minor departure from the RISCA guidance and might fall within relevant guidance from the UK LPG Association and World equivalent (I think that some of the UKLPGA guidance is a free download) + other variables that could be fed in to a Quantified Risk Assessment which in turn might be subject to qualitative risk assessment to address issues that are beyond the scope of the software that would inform a QRA - topography, prevailing winds etc etc.
Ignoring the transformer for the purposes of this message, suppose you have a 1 tonne LPG tank, it might easily be cheaper to relocate the LPG tank or one or two of the charging points than to pay for a specialist DSEAR assessment to justify departurss from the RISCA guidance - but you could probably make a judgement on the extent of "non-compliance" with the RISCA guidance to niform how you proceed and may be the decision makers might come to a "do nothing" position - and possibly that is the right conclusion for the site and its constraints.
Almost everything in this decision making is about achieving what is reasonably practicable or "ALARP" - and it is time to brush off "R2P2" and start looking at the bits on what the Individual Risk of Death ("IR") is and whether that sits in the "Broadly Acceptable" or some other range.
Good luck, Peter