Well i've ordered some of that mic cable and the reistors I need to convert Greys into Hi Imp which will sort it out for sure.

But I did check my earthings around the engine and bay, I get less then 0.5 ohm's of resistance everywhere (between Batt -ve and random locations), and 14v with the engine running (Batt +ve and random locations), again this is everywhere in the bay, block, gearbox, inlet, inner wings, bulkhead, etc..
I have also moved all my earths for MS and sensors to the battery negative terminal, the only thing earthing out to the manifold now is my oil temp sensor, and Lambda.

I do have less noise on my TPS now (as I had a litte fluctuating +/- 1 all the time), but I still get VR drop off's.