Re previous post:
Ok having looked at it more carefully I have managed to seperate the 2
parts (also better images below) It is off a Kirby vacuum shampoo water
tank, it is an on/off `valve`
My thoughts are to insert a couple of pins (dovetail layout) to support
whatever epoxy will stick to the plastic and fill the void at the bottom
left hand image.
There is no reason to have to disassemble this part later on so a
permanent fix I am hoping for.

Any further thoughts welcome?

https://imgur.com/a/IlPyXtY