Oh dear, oh dear! The plot gets worse. Notes is a total sync travesty.
After doing everything mentioned on this post and much else besides, see below, I decided to once again sign out of icloud on all my devices and delete all traces of them on each, theoretically leaving just what i had stored in iCloud in the cloud itself. Fingers crossed!
Then i began re-installing iCloud on each device (iPad air 2, iPhone 7, mac pro, macbook air) signing in and basically downloading all content as new from 'iCloud in the cloud' to the device.
In the process of this mayhem i also managed to totally delete my iCloud Keychain, so this has also been set up from scratch and each device enabled with the new keychain, i guess with all passwords effectively deleted and a clean keychain to start all over again with.
I really, truly thought this would do it, and that my Sierra laptop would now play ball nicely and sync Notes TO and FROM iCloud like all my other devices were.
But NO and not only that, now my other devices have decided to stop playing ball too!!!
To test, I used each device to write a new Note. Results as follows:
Mac Pro under El Capitan: Note written here synced TO iCloud and TO all other devices. The only one thats behaving, my trusty ancient MacPro3,1 running El Cap - what more can i say?
Macbook Air under Sierra: Note written here NOT synced to iCloud nor ANY other devices
iPhone 7 under iOS 10.2: Note written here NOT synced to iCloud nor ANY other devices
iPad Air 2 under iOS 10.2: Note written here NOT synced to iCloud nor ANY other devices
So, its great, my attempt at a clean slate, as suggested by several here, has in fact not only NOT worked, but has completely screwed up everything else too.
Any ideas? Otherwise I think its really time to call it a day and pay Evernote to do the job.
This is what I had done previously:
After trying everything thats been posted here I just went the whole hog, wiped my Sierra laptop, erased the drive and did another clean Sierra install from scratch. Logged into iCloud on the laptop but STILL anything I write in the Notes app on the Sierra laptop will not sync up to iCloud and beyond, to my other devices, whereas everything else is syncing with it fine, i.e. from icloud/other devices TO it. Now Im really scratching my head and not happy.