Dyl:  That exactly what i thought.  The ONLY thing that i can put it to was that because i was travelling at 100kmh the air was cool enough going through not to disturb anything and when i got into the city and started slowing down in traffic and whatnot, that's then it would have spiked.
I ran the engine through with the coolant for about five mins keeping the revs around 2k - 2500 and everything sounded ok.  Also noticed that the fan for the intercooler wasn't spinning......
 

unplug the ait temp sensor on the underside of the engine bay lid, this will get the IC fan to run all the time.
 
if you boiled all the coolant out or you lost it all due to a leak i don't like your chances of just refilling and off you go. fingers crossed tho.

Sounds like something similar that happened to my car. Fill it with coolant and get a pressure test done, take out the spark plugs and shine a small torch down the spark plug hole, watch for any water coming into the cylinder. If its not a BHG you might have a small coolant leak that only dumps water when the system is hot and under pressure. Man, I hope it's not a BHG but a comp test and pressure test will tell you the story. Good Luck.

I think a tow is in order.  The hardest thing will be trying to get it onto the truck.
 
Wish me luck peeps :)

Update on the SDub?