Have just tried the aux input in the jumbo box, but all I can hear is like a feedback noise and very faint music in the background.Any one got any ideas what this could be?

I seem to recall there is a AUX gain setting in my Stream MP3 Audio menu. If you have the same HU, simply go search for it

sounds like a dodgy socket or cable, like it just wants pushing in a bit further

on the aux in display press the bottom right screen button which has a black arrow next to it on the screen and change the setting to no. 3 .

Try using another cable in case its a bit dodgy. The same thing happened on my L&K - dodgy lead that got jammed in the lid hinge mechanism

As others have said, you can control the gain of the input which will help with the music volume level (it's a nice feature because it allows you to "match" the volume of your AUX input to other sources, so if you switch inputs you don't need to adjust the volume as much, if at all), but it sounds more like a connection issue in your case!

Thanx all will try a few of these suggestions out