ENGLAND IN WARNING TO HITLER GERMANY Carefully Phrased Note Is Sent Against Military Interference In Austrian Plebiscite LONDON, March 11 (AP)--Britain today gave a mild, carefully phrased warning to Germany | against military interference in Austria's Sunday plebiscite on independence. Official British sources said reports had been received of "certain movements of troops in Baand that Britain had expressed to Germany the hope that the purpose of such movements was to preserve order on the Austro-German frontier. Officials declined to say specifically to whom this view was expressed, but it was believed that it had been presented unmistakably to Joachim von Ribbentrop, German foreign minister, by foreign Secretary Viscount Halifax and Prime Minister Neville Chamberlain.