Hi Tom, thanks for this.
It looks like the problem is with the ‘hide when scrolling down’ option.
I added the css code you gave me. When ‘hide when scrolling down’ is not used it works as it is meant to with no bounce.
When I use ‘hide when scrolling down’ the css you gave me does make it a lot better but there is still a slight, but noticeable bump when scrolling down slowly but nothing like as big as it was before.
At the moment I have left the ‘hide when scrolling down’ option ON.
Cheers