iCloud Keychain won't turn on

Hi all, hopes someone can help.

Ive just set up and old laptop with Catalina totally clean instal, I used my Apple ID during the set up process (2FA approved via code on iPhone) and everything ran fine and enabled apart from iCloud Keychain. Two factor authentication is set up and running. So I attempt the following:

Open System Preferences > Apple ID

Everything has blue check box bar KeyChain 

So click to enable keychain and get the following prompt….

iCloud Keychain uses end-to-end encryption. Your Apple ID settings need to be updated so this MacBook Pro can use end-to end encryption.

Click continue and get prompted for Apple ID password. After entering I get a grey tick in the box next to keychain (not blue like all the others. Now if I exit sys prefs here and go back in then Keychain is not selected. However if I remain on the Apple ID - iCloud prefs panel after around 5 mins I get a prompt asking for the Macs password. So I enter this four mins more and it request my iPhone passcode…(so entered) another 5 mins for this box to disappear .. and still only a grey tick.request ID password again…. Now it deselects keychain . Asks for password and the passcode followed by nothing

Incidentally have erased the drive and reinstalled twice to see if that helps and it does not.

Any one got any ideas?

Cheers

Steve