Do you not have lifts or escalators in Department Centres or Commercial Buildings in Zurich? ....if so look up
KRONE...they are a worldwide manufacturer & service group for elevators, escalators & lifts.......[you may find then over the Border in Germany.....but that is just like driving from Wollongong to Sydney
]
Another source would be Security Alarm Systems providers for buildings......they would also have
hundreds thousands of batteries to replace each year
These emergency [trickle charge] alarm batteries are never used apart from 6 monthly signal tests.[or in an emergency
]......however emergency Standards dictate that these are replaced strictly on a time basis
I know
KRONE escalator's and lifts are in Sydney + Adelaide + Wollongong just to name those I have seen
Alan Bond is a member here on MBM.....why not ask him for the confirmation you need with the sound generator questions....he seems very helpful in his replies here
Whichever potential source you find for batteries, include your
https://www.facebook.com/fvcorneliamarie link.....that will, make them stand up & watch