That does sound a ball ache! I’ve got a pulley with taper lock bush coming, il make sure it’s clamped up tight!The brake 'lever' does not have much clearance (2-3mm at most) , my pulley came loose recently and started rubbing.
With mine back against a wall its pain in the arris to get too and sort, I have used a new key and double grub screwed with the hope it wont move again.
Those sockets on the back is nice addition, easy connection for the head unit![]()