For anyone turning up here in the future, a solution + details are in this thread: http://www.uklegacy.com/forums/index.php?/topic/149594-instrument-cluster-bulb-change-on-geniv-legacy/
Basically all you have to do is screw the front needles clockwise a bit, and then pull them off, and the PCB seprates from the housing. Then to change a bulb, it requires soldering in a 3528 SMD LED in place of the old one.