Extra information:

Had headlights on while trying to start it - It was cranking hard, just didn't wanna fire, lots of clicking.

Turned headlights off - Cranked up first time, problem gone. Will replace the battery this weekend.

I've noticed sometimes when i have my headlights on when i start it, one of the HID bulbs doesn't come on until i turn the lights off/on again ... related? Maybe.

While i was running a ECU Scanner, it was reading a fairly consistent 14v. Drive around with my lights on often, no real signs of alternator issues, everything looks nice and bright, added an additional earth a few months back.

Battery is old, and quite small .. But never really has any issues cranking.