I tried a couple of things... I stopped all Flows and left it for a couple of days. All was fine. Then I started one of the Flows. After a day or so I got the not responding message again. I stopped that flow and left if. Once again all was OK. I then chose a different Flow, and after a day I got the message again.
I've also had a few occurances when I get a message saying that I don't have premium (or similar message), but when I go into Automate it say that I do.
If there is anything else I can do, please let me know.
Thanks