In reply to Tib:
Mates of mine had there stuff nicked from there several years ago. I've not been passed in a few years but I can't imagine the situation has improved as the forestry gates are usually left open so it is easy to drive in.
I'd probably chance staying there, especially midweek, but I'd definitely not leave anything there during the day*.
That said my preferred option would be to camp on the E store at Loch Enoch and walk in from there - avoids crossing the Silver Flowe SSSI too.
* goes for almost all Galloway bothies unfortuantely