My name is ***** ***** will assist with your query today
I apologies William, it appears my last response didnt get through to you.
The issue you are seeing is most likely due to a hardware issue on the AV control board.
Wigan is a significant area, can you please provide me with your postcode so I can nominate a suitable local TV repair centre for you.
I have had a chat with our local engineers, they said they feel its 60:40 in favour of it being the plasma screen rather than the control board, and as such with your model you cant get to the screen as they are vacuum sealed, and due to the age of the unit think it would be uneconomical to repair.
As such the advice from the engineers, is to put the money to a new TV.
If you would like me to recommend a suitable replacement please let me know.