I think the older men with medal ribbons are from WW1 and the younger men yet to be called up?
I live Harrogate 'North Yorkshire' which was 'West Yorkshire during the war and after till 1976! but I do not recognise the location? There is a Foster Sq in Bradford.
In fact I would go as far as suggest the old GPO building on Foster Sq. which may well lead this to be a 'GPO' Company??