Took it in and replaced the waterpump and thermostat, bled and re-filled the coolant lines and it is alllllll mint. What's more is that I didn't damage anything because it was a crisp night with smooth freeway driving at 100 km/h below 2.8K revs so the engine wasn't close to being at max temp.
I will admit now however that JUST before the light's came on I was flogging the car quite hard - quite quite hard.. so after I dialed it back the car made it home no problems.
I even got a pretty good deal for parts + labour at 865+ tax = $953 CAD and got it back after 4 hours.
Car feels solid. Thanks everybody.
6MT Sport Pkg | BMW Perf. Pedals | BMW Perf. SSK | CF Steering Trim | BMW Performance Black Gloss Grilles | M3 Rep Bumper | Muffler Delete 2.5"| Charcoal Delete + K&N Drop In | CDV Delete | Clutch Stop | Active Autowerke Stage II Tune | H&R Sport Springs | Koni Yellow Shocks/Struts | 18" Gunmetal CSL Reps | BurgerTuning Spacers | Staggered Ventus V12's | ATE Super Blue & Hawk HPS | Blacklines | GP6K Angel Eyes