Add Listing (layout Issues)

I am using the latest version of the premium-press directory. I have added a variety of custom fields using checkbox. These are displayed on the “Add Listing” page but I cannot find how to adjust the column widths as the checkbox is covering the wording/choices.

Website is http://www.ukaquaticshops.co.uk (go to add listing and within description box to see issue). Once updated the selections are fine on the listing page. I just need a way to adjust the layout or width of each checkbox area.

Many thanks in advance