A quick google reveals that Union Chapel still exists, though it doesn't look like this any more.
Posted in Wolverhampton in August 1909, Miss A Gobourn is Ada, who would have been aged 20 at the time. She went on to marry a William Rowley in 1915. Marion's identity does for now remain a mystery, she's not a sibling as far as I can tell, so obviously a friend who gave Ada the nickname 'Go'.
As the card is mailed from Wolverhampton to another address in Wolverhampton, I wonder if postcards of Manchester were for sale all over the country or whether Marion had visited Manchester.