Hi,
The picture below is actually a cooker outlet plate, available from any electrical spares supplier. It is, in effect, a blanking plale with a downwards facing hole that allows cables to exit neatly - ideally into a cable cover of some type - the flexible rubber or expanding sock types work well. They will exit down and "sweep" nealty accross to your product. Ideally fitted to a single pattress, they can also be glued over cables already in place that just poke trhough the wall.
Although we don't use these as a first choice for installations, they can be useful for remedial work for jobs like yours, when you need to hide previously done work. The Volex one below has a decent sized exit hole.
Regards
David
Bang & Olufsen of King Street - Manchester,UK. SKYPE - beokingstreet