The thing popped up again even though I have already told it twice asking if I wanted to stay on the mobile site or go to desktop.
I have no idea why but I pressed 'Go to desktop' , then to make it worse I pressed 'yes always' head not screwed in tonight . 
So now I am stuck on the desktop site, which does my head in!
How do I undo the damage and get the mobile site back???
I neeeed it!!!