OK I've been on the phone to Apple Support and they've solved it for me. All I needed to do was to change the note syncing from iCloud to my Gmail account (and other options may work, too?).
First on my MBP: System Preferences - Mail, Contacts & Calendars - click the service you want to use on the left and side and log in, then select contacts. Open Notes, then select all and drag & drop onto new account (on far left). Wait until you can see they are all there and they have synced.
Then on iPhone: Do same.
Then on MBP, then on iPhone: unselect Notes in the iCloud account it says it'll delete them from your phone but that's OK as you still have the ones from the other service.
Sorted.
Good luck, just make sure you back up your notes in case something goes wrong??