In the book "Rail Centres: Doncaster" by Stephen Batty (Ian Allan, 1991) there is a picture taken from a similar angle which shows the canopy in place (although maybe partially dismantled) over the Down platform road but the one over the Up side has been removed and steelwork for the new canopy is in pace, in other words it looks like 'work in progress'. The caption gives the date as 31st May 1957.