Yup, it was full right to the top of the barrel. I cleaned it out, the sawdust and shavings can be disposed like our other waste, wherever possible, I just bail the shavings out of the barrel into trash bags with a dust pan.
I resealed and screwed the panel to the bottom of the filter tube, the latches were getting a little worn out. I did a quick suction test and noticed a small dust leak around the motor and fan housing. It doesn't seem too serious for now, but we know why there's always dust in the shed.
Thanks for the reminder, Tim!