Right, as things stand from today.
Unit powers up fine.
All speakers are wired in properly, all speakers work.H/U is fine as i've tried it in my van.
The speaker cable loom in the car has 4 pairs of cables, 2 to each speaker, but within the loom there is a 9th cable. When i touch this on the rear right speaker connection it works.
Turn the H/U off and back on again i get nothing. Take the wire out and put it back in and on it goes.
Well stuck for ideas now......