In answer to my own question... I drilled three small holes in the back face, left side bottom of the ashtray, drilled bigger and dremel-ed out a slot. Through that I fed a USB cable (from the inside). The cable goes down the join in & then under the carpet between handbrake and shifter to a socket that was fitted ages ago on the tunnel. Inside the ashtray are now three charger cables (micro, USB C and lightning) that are hidden when not in use and easy to access and use for charging in the console tray.