Buzz from Remote Lead

There you go, you hit the nail on the head!  Refer to the hundreds of posts on alternator whine.  Check your grounds!  If I had to guess, based on the loud pop you hear when the system turns on, I would say try adjusting your gains.  One of the biggest noise problems is caused by the misunderstanding of what input gain really does and how to use it.  Turn it down and see what happens. 

Laid both sets of speaker wires flat and taped them to the floor, there ground i have moved and still no joy.

Seems it's got me beat..............

Rear is grounded to the frame via a bolt into the chasie, the the head unit is fine.

It;'s the noise from the engin I cannot get rid of so the lot is comming out, never been one to mess about.

If any one as any other idears just let me know. I'm toying with getting a stand alone battery in the rear?

Almost all alternator noise comes from a ground loop, meaning different components in a system grounded in different places but all tied together thru audio cables.  You say your HU is fine.  If it isn't grounded IN THE SAME PLACE as the amp, there's a good chance that's where your noise is coming from.