Hi Rob
We are no experts here, however I would guess that you are responsible for the safety of your team. If there is a substantial fire risk at the client's premises, surely this must be of as much concern as if there was a risk of personal assault. Some form of basic fire safety awareness training for your staff would probably help. Whilst not a classical fire safety risk, your staff ought to also be made aware of the dangers of carbon monoxide poisoning and how to recognise low level symptoms when they are visiting. This would protect your clients and team
Harry