Hi Mike. I've got the same on mine. They're a 'sports rack' so don't put anything too heavy on it.
Hi
Yeah I realised they weren't attached to anything at the rear so are kind of suspended by the two grab rail bolts either side of the seat.
Will it take a small topbox or would that be pushing it too? I never carry much in it, it's mainly for small shop runs or putting my helmet and gloves in when in the shop. Most of the time it's not attached.