Thanks very much for the replies
There is no visable damage that I can see, but is there anything visable to see when the aperture ring is set to A? The aperture blades still work and I can set it to A aperture but the camera doesnt recognise that, just has -- for the aperture info. It also asks what mm the lens is when the stabilisation is selected.
When turning the focus the little part for the af rotates too.
It really seems like something electrical inside it has been knocked out. Has anyone fixed the circuitry of a lens before? I'm assuming microchips shouldn't be damaged as it wasn't a great drop, just maybe something came loose.
The one thing I'm not sure about is that if I turn the aperture ring the full range, around the middle it's a bit stiff. I can't remember if it was like that before.
Apologies for the quality of the photo. The aperture ring is set to A.