Which supply? Mine has a ciggie socket hidden on the back - you won't need the adapter cord.
I doubt you'll find a commercial lead. Want me to make you one? I'll get the following from Jaycar:-
CAT. NO. PP2007 Cigarette Lighter Socket to Battery Clips $9.95
CAT. NO. PP0400 Red Banana 4mm Plug $0.95
CAT. NO. PP0402 Black Banana 4mm Plug $0.95
So $12 in parts.
Free labour - as long as I can keep the two croc clips I will cut off. PM me.