I don't quite follow the numbers being proposed in this thread
Initially, it was 370km a day for 7 days (?) which is 2590km
The shortest route for lejog is 1390km, 1500km seems like a reasonable guess when avoiding some of the crazy A roads or diverting to nice hotels
I'll be using the shortest route within reason and my Dad will be following me hopefully in a campervan. I'll fall off the bike into a bed for 4hrs or so.
400k a day is about right. I think it is possible for me, others may disagree. It doesn't hurt training hard and giving it a good go.
It's a good target to aim for. You might be able to do it, you might not. It's a big step up from what you've done so far so the odds are against it but it's not impossible and you won't know until you have a go. Good luck!
Did you follow kristof Allagaert' s ride last year? He had a shot at the record, which is five and a bit days, riding unsupported, and missed it by an hour or two.