EMISSARIES from the Scottish city of Aberdeen have returned virtually empty-handed from a four-day tour of northern England to try to lure teachers to fill up to 20 vacancies in their secondary schools. In Bradford, Warrington and Carlisle, not a single teacher registered an interest, despite the 35-hour week in Scotland. In Durham, however, some did show up. A spokeswoman for Aberdeen said bravely that the event had attracted good media coverage and so was not considered a waste of time.