LIBBY GEORGE A London court has given Nigeria more time to appeal in a $10 billion arbitration case, although Friday's Commercial Court ruling did not specify the length of the extension in the long-running dispute. Process & Industrial Developments (P&ID) won a $6.6 billion arbitration award after a 2010 deal to carry out a gas project in Nigeria collapsed. This has been accruing interest since 2013 and now totals nearly $10 billion, which if Nigeria has to payout would dent the oil-producing country's foreign reserves. Nigeria has alleged corruption in the contract and the ruling will allow the government more…