This is great, thanks for all the options! It's currently a handheld shower head with a fixed bracket (fixed in a stupid place and very unadjustable) so depending on what we can find separately I'll either do a slider bar or an adjustable arm.
How do fixed brackets usually attach? Because the current one doesn't have any visible screws and I don't know whether to try and remove it or just leave it there (as it's further over to the wall than we want it anyway, so it wouldn't be in the way for the new one).