By Lars Mucklejohn Sir Richard Branson is set to receive upwards of £650m from a potential takeover of his challenger bank Virgin Money by Nationwide, it has been estimated. The two lenders announced last week that Nationwide had agreed terms for a £2.9bn takeover of Virgin Money to create the UK’s second largest provider of mortgages and savings, with shareholders set to receive 220p per Virgin Money share. Branson stands to receive an “exit fee” of at least £250m from Nationwide on top of the £400m valuation of his 14.5 per cent stake in Virgin Money under the preliminary agreement. The bill…