Barclays is reportedly having trouble unloading a stake in its U.K. merchant payments unit.That’s according to a report Friday (Sept. 13) by Reuters, which cited sources who say the difficulty is down to differing views on that business’s valuation.Brookfield, which manages more than $825 billion in assets, was one of the private equity firms that walked away from bidding in recent months, chiefly because of Barclays’ asking price, two of the sources said.Other sources said that the negotiations have been c ...