12 volt accessory power plugs

They come in a few different versions, the original Hella ones are around $14 for the socket and about half that for the plug, Jaycar sell their version which while they aren't the same quality seem to do the job and supercheap have another version which is also cheaper but is still far better than a fag plug and socket.
Electric Boat Parts sell the good ones as do other marine suppliers as well Hella agents.

Aaaaand ........................

Whitworths Marine !!!!!!!!!! And reasonable cost ..................

try Dereks ABR, I reckon he has them, www.sidewinder.com.au I think and he's is a regular contributor on here too