As it was a one off job I couldn’t justify a dremel. So I drilled it diagonally to finger width. Then using course sandpaper wrapped around my finger I was readily able to enlarge and make it circular. think I made some minor scratches on the inside of the storage box while working on it. So if I went again, I would apply some tape or clear contact to the area beforehand, to protect it while working on it. This would also allow me to draw the exact shape on the contact while it was on a flat surface then stick it onto the confined space in the storage box.



Top RHS shows what I ended up with. A flush USB charger, beside the AUX IN in the Armrest storage.

Bottom RHS is the harness I made. 1Amp 5V USB charger at one end and a fuse tap and ground point at other end.

Bottom LHS shows the fuse tap in the cig lighter slot and ground under the bolt that fixes fuse box. Can you electronic types advise me if this setup is flawed. Seems to work fine.

Bottom Center. Just to show that a connector at this end is essential. Because you have to install the storage compartment in the car before you fit a) the USB and b) the AUX IN. Conversely you have to remove them both, prior to removing the storage. This is because they foul the attach point that the screw in the third (square) hole at the top goes into. AUX In has a similar albeit smaller vw connector.

Again. Thanks again for all the advice.