By Jessica Frank-Keyes Rachel Reeves’ plans to increase social rent may not “move the dial in a material way” on council housebuilding, a corporate finance firm is warning. The Chancellor will reportedly up social rent by bringing in a decade-long formula to raise housing costs in England boosted by the CPI inflation measure – currently 2.2 per cent – plus one per cent each year, according to the Financial Times. Reeves is expected to announce the proposals in the October budget, and the government hopes the plan will improve affordable house building rates by assuring councils cash flows. Cen…