UK Bell Box for ZWave Siren


I’m finalising my hardware for “Phase 1” of my HA rollout at home.
I’ve decided to go for a battery backed Indoor Siren, but want to mount it outside in a UK Alarm Bell Box.
My Siren of choice would be the Vision Wireless VISEZM1601-5 and It’ll be mounted under an overhang of the roof on the front of the house.
I’d like to hide it in a standard UK Dummy Alarm box for weather protection (i’m aware that it won’t stop slugs) and for optical deterrent.

Does anyone here have experience with bastardisations like this and can probably point me to a good dummy box?