Well I got the panel lights working eventually but it was not that simple.
Whether it is all wired correct at the main fusebox was hard to know as the radio aerial had seized and the owner had removed the fuse as it kept blowing if radio turned on.
As a result he had just fitted CD player into the glovebox with a flylead to add the MP3 or iPod and a couple of speakers under the dash facia and done away with using the radio albeit still fitted.
Now that is where the search finally took me sorting out the panel lights.
Whilst there is a 10 amp fuse for panel lights/control unit and dimmer circuit clearly marked in the fuseboard the actual supply to the relay is/was linked to the 10amp fused labelled as radio/aerial. So without this fuse in place the panel light relay would not energise to make the panel light control unit and dimmer send 12v to the panel lights which supply comes from the fuse marked as panel light.
So what started as a panel light issue ended up with me removing aerial cleaning shafts and regreasing the aerial motor so I could get that fuse for aerial/radio back in place. Anyone that has done this also knows it means dropping the wheel arch liner so a big job.
That then I thought would now solve the panel light illumination problem..... but alas whilst I now had supply to the panel light relay and it was allowing the Dimmer potentiometer and control unit back with a supply link the control unit was still found faulty.
That fix actually though was quite simple and exactly what Shadow11 ended up having to do.
Just remove the red and green trace wires with the two spade terminals and discard. One is from relay one from control unit.
Also remove the twin red white trace wire at the control unit and fit direct to relay in place of the red/green wire and this will then give power to panel lights at full illumination at least.
My intention was to do a circuit repair to the panel electronics light control unit but the whole bracketry it is embedded into has fuel pump and other relays attached to it so seems to also act as the heatsink for the control unit and a huge bracket for all the relays.
Given the time constraints of fixing other things I decided to order a second hand unit which is NOT gauranteed functional but was cheap. It comes with all the Lucas relays so I can now check/repair and have it ready for the next time my friend visits and we can just do a quick changeover and then I will repair his unit too and hold for a spare for someone later.
My friend left quite happy last night with music playing from the radio, and able to see the gauges/dial in the dark now.
Thanks for all the support on issues but just wondering if someone with later SS11 could just pull the radio/aerial fuse on their car and see if their panel lights do go out which would confirm my findings on different fuse supply to relay.