EC MAINLY FOR TIN EXTENSION, NO U.K. STAND TAKEN European Community (EC) members of the International Tin Council, except Britain, have said they are prepared to back an extension of the International Tin Agreement, an EC spokesman said. He said at a meeting of EC states' representatives here yesterday, Britain undertook to communicate its own decision to its partners today. It said it was not ready yesterday to take a stand but did not say why. He added nine other EC states backed an extension. Spain and Portugal, which are not members of the International Tin Council, raised no objections to a common EC stance in favour.