Another update. I have today spent a few hours working upon the meter/dash assembly once more. I have replaced most of the standard bulbs with LED's with the exception of the 'Cruise On', 'Cruise Set' and 'Low Fuel' warning lights.
At this stage everything works exactly as it should so, bearing in mind the ongoing problem I have been having, would suggest that the resistor bridging the low fuel circuit is incompatible in some way? I can confirm the resistor fitted is 470 Ohm 1/2 Watt. Maybe the value of the resistor is incorrect? I'm just not sure! Maybe someone could advise with this?
I really would have preferred to replace all the standard bulbs with LED's but, without a solution, think I'll just leave the bulbs in these three warning lights, for the foreseeable future at least.
I will also say that I agree with Briese that the Main Beam and Neutral warning lamps (fitted with LED's) tended to be a little too bright, so I removed the green and blue lenses from the front of the meter assembly, (they are just a push fit) and glued some diffusers, cut from the same milk carton used for the internal diffusers, on the inside of these and they work brilliantly. Just a suggestion for anyone else who has a similar issue?
It certainly looks like I am making progress and would like to thank all of you that helped and advised along the way.
Well everyone. It looks as though I was premature with my post. Once again I thought I'd located the problem by removing the resistors and LED's as mentioned in my post. But no! After leaving the cluster connected for approximately 24 hours, I have just switched the ignition on to have what I thought would be a final check, and the issue is still there.
A fellow Winger in the UK is hopefully sending me another cluster. My next stage has to be fitting this and see what happens I think?
If anyone has any further ideas then please comment