After a sniff test, thankfully the fluid didnt change colour so Im relatively happy. There is no water in the oil or oil in the water so im reasonably convinced the hg is not the issue. Upon further inspection of the rad cap, its cattle trucked, the spring bit dont spring any more as its missing!! I have deduced that this is the possible source of the problem. So, to combat it, im fitting the 56mm core ally rad, if it fits, then swapping out the turbo for my low mileage ct26, which inturn will be bolted to my shiny tubular manifold, ill be bolting my aussie decat to the back of my turbo and finishing it all off with my blue flame system. That should start to put a smile on my face.