Forrestdale Barn Shed
I'd previously been told that this was once the Armadale West Fire Station but there's no evidence to support this.
Built in the late 1980's in a semi-rural area, the neighbouring properties all appeared to be used for cultivation. The site itself didn't, so perhaps this shed accommodated workers for a short duration of time before it was used for storage.
It appears to have been abandoned from at least 2019 and perhaps years earlier, notwithstanding it's uses may have been fairly simple leading up to its current state. The whole area is continuing to be developed for semi-industrial businesses, so it's just a matter of time before this trashed barn shed is demolished.