Well apparently all I needed to do was post on MR about my problem! While waiting for a response I signed out and resigned back into the Kobo app and it worked.
I don't know why it didn't work previously but this time it did. I know that I have done that at least twice and my husband has also signed out and back in several times as he can't remember my password and had to ask me every time.
Who knows but it's all good now.
