Is the free bus to Sainsbury's still running? I heard that it runs from the underpass on wednesdays starting from 10am. I tried to catch it last week at 10am and it either was late or didn't arrive. No recent information about it online.
It does run from the underpass. Follow the trail of people with orange bags and you'll see a double decker bus (normally at the Eastern end of the underpass) with "SAINSBURYS" on the sign at the front.