Why have I only just noticed this?
Most sprite strip dialogs give you an option to set the x & Y offsets for each individual sprite as well as how many per column and row. This is because many of the stripe strips of old had a borders around each individual sprite.
This facility exists for the Tilemap object but not for the sprite strip import, which is a shame, as I really need it at the moment.
Just my gentle Monday rant, as I know this will never be implemented for C2 now, but it is also missing from C3, so fingers crossed.