Its quite easy. Open the armrest and pull out the insert. Then you will gain access to the electrical plug for the socket. To remove the socket, there is a special tool, but thats is quite expensive.
I just manhandled it out of there with a pick and flatblade screwdriver. You will mangle the unit, but I had no intention to re-use it. The lighter is more or less hooked into place.
Off course: remove the electrical plug first before you start attacking it with a screwdriver
Aftermath
The hole has a flat bottom, you need to grind that out for an aftermarket solution
That was my first solution, but that unit needed to be switched on everytime, which I found tedious