To be honest, I think you can dump the Diode, as it will only protect you if you manage to connect the charger up the wrong way. But if you are using a molded plug /socket affair that is hard wired to the charger this shouldn't be an issue. I am a little worried about the battery packs hardwired together. I suggest that you stick with a single pack, but with a bigger capacity. Re the LED's they will make no odds, but why the green one when the headlights flash on power on?
Otherwise I'm completely in agreement with darkith.

Yours Simon M.