I have been in exactly your position Graeme, so I understand your frustration. Your customer is putting themselves in a position that they may come to seriously regret. The other advice won't absolve them from ultimate responsibility.
You have done everything expected of you and you can't do any more, based on the way these things work these days.
What are your own suggestions as to how this sort of dilemma could be solved?
I will try Wiz-here goes.
I feel that the stage we are at now with fire systems is that the engineer who signs is the engineer who is the person who carries the can if something goes wrong.
In theory this should only produce good engineers who if have any sense will never sign off any job he/she is not 100% happy with or in the case of existing systems highlight every possible flaw in the site.
As this huge responsibility now falls onto a single engineer not a business then the engineers should be given more respect for the knowledge of a fire system they have,in most cases more than a risk assessor does.
What he recommends should not be overridden by someone looking at the system for the view that "it will work in a fire if needed" but an engineer view of "that won't work if this happens" etc.
Yes there may be afd on this site but this does not take into consideration that they are 20 years old,ten years past their recommended working life.
Most probably will work but in my experience as in B+B's and carehomes, some don't,some become more sensitive causing unwanted alarms,some become less sensitive and most this age are ionisation which due to it's sealed chamber cannot be cleaned fully to remove dust build up.
and the call points if there is a fire-will the person be prepared to loose a finger as there are no hammers to break the glass?
And as mentioned with Sparks. We (fire engineers) have to take numerous courses etc to make us competant in our jobs.
We are not allowed to undertake any electrical work unless we are a member of etc etc and qualified.
This is meant to go for fire now but i am yet to see it happen and i have yet to go to an install that has been done correctly and is fault free and ready to commission by an electrical contractor.
In a nut shell when a fire engineer tells you your system is a bag of spanners then take him seriously as he is not trying to rip you off but save you neck and sparks on site-don't laugh when you are asked to produce as fitted drawings with cable routes as this will save you hours when you come to fix all your mistakes and realise that your job cannot be signed off as a fully compliant system unless you produce an installation certificate,as fitted drwings etc to the commission engineer.
sorry for rant but these things are far too common in my every day life.