I don't know where OP's fear of £10,000 for the end of 2023. Certainly no responsible people have forecast that. I have no idea what the prices will actually be, but I think £10k is highly unlikely.
Having said that, I can't work out what is going on at Cornwall Insights, who have usually been fairly good with their predictions.
On Monday 22/08 they released these predictions:
Q4 2022 £3,553.75 (ie October 2022 - announced today as £3549)
Q1 2023 £4,649.72
Q2 2023 £5,341.08
Q3 2023 £4,767.97
Q4 2023 £4,807.11
These predictions were in line with many other expert forecasts.
Now, on Friday 26/08 they released these predictions:
Q1 2023 £5,386.71
Q2 2023 £6,616.37
Q3 2023 £5,897.12
Q4 2023 £5,887.31
They have given no reason as to what has changed in the last 4 days to cause these higher forecasts eg. Q2 2023 is 23.9% higher than they predicted at the start of the week!