UKH

There was a thread back in March/April but it didn't get to too much of a conclusion. See here: https://www.ukhillwalking.com/forums/crag_access/cambusbarron_thorntons_access...

The crag page ( Cambusbarron Quarry (aka Thornt...) still marks it a climbing banned, but I've heard from different sources that it's ok to climb there. I've also heard the Climb Scotland has also voiced it is ok to climb there, but I've heard this third hand. 

Is there anyone here with enough insight who could clarify? 

It's not quite up to today's standards having the the crag page say access is banned when/if it's not.

I have no additional insight other than having recently been climbing there without being asked to leave.

It's my understanding that since its not a working quarry there is no legal reason to exclude climbers, or anyone for that matter. The posted signs are a back-covering exercise. Have suggested update to crag moderator

I spoke to Burnsie (Mod.) about this just the other day.  Apparently it was only temporarily closed while they were felling diseased larches. He's on the case to get the latest from the council etc. and see when access can be restored but will no doubt update the database page in due course. Good news soon hopefully.