Between Mark Robbins and a few other people I've managed to get this working and not affecting the other clients:

This goes inside your 480 media query.
u + .body .full-wrap {
width:100% !important;
width:100vw !important;
}

As you may be able to work out from the above, my body tag has a class of 'body' and my inner wrapping table has a class of 'full-wrap'.

I've been pulling my hair for a while with this one - enjoy! :D

P.s - let me know if it worked for you??? And don't forget to upmark if it helped you so others can find!