I imagine it was purely down to luck getting a decent person when you called. some people have luck, others don't.Just had my B7 approved for replacement by John Lewis as it suffered from screen burn and a replacement screen is not available. There was no quibble about it and I have ordered a CX. The cost to change was just £200 as the B7 was discounted for the best part of three years use. I could have had the C9 but felt the 2020 set would possibly have better screen burn protection.
Where I am a little confused is the additional insurance for £140 which appears to be good value. My original warranty from September 2017 didn't mention screen burn. Later policies appear to have had that added. The unknown for me is whether they honoured the original policy or this was a one off exchange based on the bad publicity that has appeared in the press. I have home contents insurance including accidental damage, so the only reason to buy a new policy is to ensure another replacement should screen burn happen again. I'm assuming all standard policies now specifically exclude screen burn, hence the opportunity to buy additional insurance.
Model wise, I always felt our B6 had a better picture than the B7, but that may be down to screen burn. It will be interesting to compare the B6 to the C10.
At least with the new £140 protection there will be no if's or but's if it was to happen again... also covers you for accidental damage as well a no brainer for 140.