I have checked on the Chorley Council website https://www.chorley.gov.uk/Pages/AtoZ/Chorley-Markets.aspx
and it says that a street market is held on that section of Market Street on Tuesdays. So from that gate to the Junction of Saint George's Street there will a restriction - my guess is 0700-1900 Tuesday Pedestrians Only.
I know that it is closed on other occasions such as fairs but they are irregular.
Today is Tuesday so I'll go there and find the details.