@Remarka6le Thanks for your reply. I just tried another key and that didn't help. The strike plate is probably a little wonky, but the bolt always goe ...

Thanks @MitchellMc. I didn't know those existed - they look like a good solution.

Thanks for your suggestion @JoeAzza . I tried turning the roller away from me and towards me and neither way made any difference. There is also no 'wh ...

Thanks @MitchellMc. I am aware of the vertical play between the blind and the mount. I explored the right hand side with a small flathead screwdriver ...