Hey guys,
Sorry kdisc98, I hadn't seen your reply before I posted my last one.
I did a test where I disconnected the device I was trying to blacklist and then quickly ran the 'stm add-blacklist-client' command and it is now showing as permanent!
All my previous attempts were with clients that were currently connected to an AP.
I suspect that inside the VAP profile I definitely have a different value as I wasn't even aware that there is a value for the blacklist timeout.
I will have to try and figure out what that value is as I would like to make note of it in my documentation!
Thank you guys for your help! I feel stupid now, it is a pretty straight forward explanation!