Firstly this happens in all themes including the generic wp themes
Secondly
“This isn’t something that can be fixed easily with a bit of CSS code”
It is terribly easy to fix and I just went into the individual themes css bootstrap min . css and change the col-sm-6 variable from 50% to 55%
job sorted…. I just needed to find what was causing it… so i spent a few hours with inspect element.
and as you can see here it is fixed
http://flystoppa.com/flystoppa-ecommerce-shop/flystoppa/fly-stoppa-wheelie-bin-kit/
explains why somebody like me wont purchase any addons if you can not get even a little help….
