BB - Wigan council (if that's what you mean by Millgate?) has no say in the rates.
The only 'willpower' that can save the market is the 'willpower' of the Wigan shoppers. 'Willpower' to make them spend their money in Wigan market, rather than in Tesco's, Morrison's, Asda's or Sainsbury's. Or, even, Bolton or Bury markets !