Yeah, when I later mentioned reinstalled, I meant everything involved (minecraft and java) My JRE is now revision 15.
After my BF3 match I came back for another try at 11:45pm. Worked perfectly fine. This morning I jumped on to check at 7am. Perfectly fine.
This is now suggesting maybe it isn't actually the router, but the local exchange perhaps? Just so weird that even should that be the case, it is only Minecraft that is affected. (Considering without any resets or reboots of either modem or PC, I went and played a competitive match of BF3 against some of the best in the ladder without any lag on their Australian server...)
The fact that it sometime works flawlessly (well, y'know normally at least :P ) gives me hope ha ha.