My Desktop is now compatible. Problem was not TPM 2.0 but I was booting from MBR disk and not GPT. Once I ran MBR2GPT for Disk 0 in System32 on Win 10 and re-tested I was getting a green compatible but lost my dual boot option. Also I will have to lookup what WinRErepair is all about as the above advised me to run it.
The checker is not very good, it seems to be more about getting people to buy new computers, it has a limited amount of CPU's in the list, so even if your CPU can one Windows 11, it will say it can't.
I can't remember what I formatted my drive to.
Anyway the more I read about Windows 11, the less I like it, not being able to move the taskbar would annoy me, I prefer mine at the top of the screen.
Adrian
Desktop machine Ryzen powered with windows 10 , reluctantly.
Plusnet FTTC