howard;
i'm a pleb in such matters, but there has been a number of suggestions such as cctv, my fear is that every time something is vanalised we lock it away, thats not a good way to go forward for the future
contact with police to get them to spend more time around the area to see if the culprits an be identified, maybe even plain clothes.
contact with locals living close to the shelter to see if they can/wood help if there around all the time
lots of options
