Animation - horizontal scrolling - page outside boundary

Hi balbooa,
My latest website has an accordion on the rightmost side of the page. Horizontal scrolling animation is enabled on the accordion, so it scrolls from the right to the left.
Before the user scrolls down, the accordion is outside the page boundary. Unfortunately, rather than being ignored, this extends the page width, beyond it's margin, so the bottom scroll bar appears.
This has a number of unwanted effects:

1) On tablets and phones (touch screens), the user can drag / scroll the page from side to side
2) If a plugin is placed to the right-hand side (for example the cookie policy in lighthouse mode), then the lighthouse box is against the extended margin, and outside the standard viewpoint. So users cannot read the cookie text.

Once the user scrolls past the horizontal animation (i.e. the accordion is in it's designed position), the margins return to normal.
If the horizontal scrolling animation is turned off for the accordion, then the margins return to normal and the page cannot be moved from side to side and the bottom scroll bars disappear.

The horizontal scrolling animation should not effect the page margins. Please see images.

Many thanks
Marc