Hello all. In response to the “blue screen” problem, please read the answer given by - '''den@techfixed4u''' on 03/16/2019 - in the earlier posts above. My LG tv was purchased four and a half years ago, but following den’s advice, I went to Currys/PC World, from whom the tv was bought, stated my reason for requiring a repair, mentioning the Customer Rights Act (2015), and they agreed to repair it without any fuss or argument!
I thought I might have to agree a deduction due to “fair wear and tear” but not so. I had to pay £95 for the tv to be collected and inspected, but if tv was found to be faulty, (which it was) then it would be repaired at no charge, and the £95 would be refunded. So I now have a great tv picture once again and a refund!
Huge thanks to den@techfixed4u and the ifixit.com website. Thanks also to Currys/PCWorld.