I think Freaky Friday may have started early, I logged out of my buying id and into one of my selling ids to find no sign of Selling Manager, clicked on sell and got the dropdown list and clicked on active. At the top is an item with a best offer so I clicked on that only to get a page unavailable message, it was at this point I realised that I had been logged into the UK site!

I changed the url to ebay,au and I was straight away back to my buyer account, this time the log out and log in again worked ans all was as it should be.