I went with this removable vintage look Bluetooth speaker on magnetic feet, now I know its there I'll see what use I can come up with for the radio void behind it.
I use the cars speakers attached to a Bluetooth Amplifier mounted under dash, so much more accessible. I hollowed out an old Radio Cassette and used it as a drawer to keep things in. The idea being that it looks like a radio and therefore the contents are hidden. The problem was that the contents bounced out, so I now use the space to hold a 1st aid kit..