The control light holder is located on the underside of the dashboard. It has three connectors; a single feed for both lights and two outgoing connectors to the neutral gear switch and the regulator. The one on my Bella was broken:

You will see this is a single bulb still in place, but the second light bracket is missing. Unfortunately it also wasn’t attached to its wire. I had to order a replacement one as I didn’t know what the remaining bit looked like. However, you can also mirror the remaining bit if you are in a similar situation and cut it from a circuit board. Here are the measurements needed from the second hand one I managed to find:

It looks in ok shape, but that is after dipping in a chemical cleaning bath that cleared up the copper as it was heavily oxidised. As can be seen the wires were cut. Luckily I could compare the length needed from my broken one. The are about 11 cm total, but you could give yourself an extra inch.

I also found that the rivets used originally were loose. So when I de-soldered the existing connections I took a punch to them to tighten them up before re-soldering.

The finished product:

Note: the holder does not have a contact point for plus and minus as is. You will have to solder a wire to the negative of the bulb and wrap it over the top of the bulb for it to work. This is how the remaining bulb was installed.