Thanks for the reply Paul. I do exactly the same as you and have one of those ultra low profile usb storage sticks for my music. I was just frustrated that the Advance model that I (and you) have won't connect for both via bluetooth - just seems illogical.
I'm not sure if other variants are the same or if it's just the Advance. There are workarounds - a bluetooth receiver attached to the Aux input and a usb charger in the power socket but it's all a little long winded.
Thanks again for your input though