If the county council are of the opinion that any highway specified in a notice under paragraph 1 above does not fall within the relevant powers, they may, at any time within the period of 6 weeks beginning with the date on which they receive the notice, serve a counter-notice on the district council disputing the right of the district council to exercise in relation to the highway concerned any of the relevant powers; and if the dispute is not resolved by the county council and the district council within 6 weeks after the receipt of the counter-notice by the district council the dispute shall be referred to the Minister for his decision.