AnthonyB

The only other manufacturer who uses the E-Series mist nozzle (under license I believe) is the Saudi manufacturer SFFECO who has a range almost identical in construction to Firebug's that include the 3 & 6 litre mist extinguishers. I've had a client who has safely and effectively used a water mist extinguisher on a live 415v industrial laundry machine fire (after CO2 was ineffective) so it's not all bluff, they are as good as they claim!

That sounds like an example of the increasingly common 'rag & tag' service engineer where nothing is inspected or tested and you are lucky if they even change the pull tag. If they remove the horn (which they ideally should to check for blockage & to weigh if the marked commissioning weight is without horn) then they should (although it's not shall in the standard) change the washer.