Dunno about the shupercheap ones but Jaycar's neons will run from a 12v power supply... i.e. you can remove the cigarette lighter plug.

Ive got mine tapped into the interior light circuit. Lol, couldnt figure out where the wiring run was so ive tapped the circuit from inside the roof lining. This circuit is already fused.

Looks kinda cool as they fade out with the int light...

Yea I got a couple from Repco...they have a sale on just now, 20% off all neons...and driving lights...hence my other thread "EL XR6 Hole"....

Anyway, I tapped into the interior lighting circuit, which is in the loom on the drivers side under door sill cover. Very easy to do, and looks great as they come on when the door is opened and they also fade with the interior lights!