This has been a long term on-off project but is finally back again (for good hopefully).
Having deliberated for some time how to wire up the electronics, I decided to use an internal battery, hidden inside one of the engine pods. This is just big enough to hold a 3V lithium CR123A in a couple of spring clips attached to a piece of strip board. The top fan cover of the engine pod is a tight fit and will remain in place until it needs to be removed to change the battery.

 
A small push-on push-off switch that was salvaged from a bit of electronic junk was mounted in the rear of the fuselage, with just the actuator protruding underneath. This provides an unobtrusive means of switching the lights on and off.

The fibre optics for the 2 tail lights were mated with 3mm LEDs (one red, one blue) inside some small pieces of aluminium tube – this holds the fibre securely in place and also cuts out any excess light from the LEDs.

I will be using Alcad II chrome to give the HK as shiny finish as possible. This means everything must first be base coated in gloss black enamel. I decided to do this whilst the kit was still in sub-assemblies since it will be hard to get in all the nooks and crannies once finally assembled. The fuselage halves will need to be assembled and joins cleaned up before Alcaldding, but this will first require the controller board to be programmed up with the desired animation code.