basket won't scroll to bottom everything-supermarket-r39(17-Sept-2018)

[Jillyann]

If you add a lot to the basket on my site, thesquarepegonline.co.uk, the basket scroll will not let you reach the bottom in order to proceed any further and pay for the items selected.  You can only proceed to check out from the last item purchased or right click the basket to open in a new window.

Hoping someone can help with this!