By Huw Jones LONDON, June 17 (Reuters) - Britain's Labour Party said on Monday it would give regulators new powers to significantly increase the number of 'banking hubs' on high streets if voted into government next month. Lawmakers in Britain have flagged concerns about the closure of branches leaving some people, particularly in rural areas, facing difficulties accessing cash as many customers bank online and use cards to pay in shops, cafes and petrol stations. Banking hubs are located in communities across Britain and operated by the country's Post Office,...