THE Malaysian Prime Minister, Dr Mahathir Mohamad, said he would combine some work with his holiday when he began a two-month vacation on May 19. So far, he seems to have been devoting more time to formal duties than leisure activities. With his official engagements featuring prominently on the front pages of Malaysian newspapers over the past few days, he has often been upstaging Anwar Ibrahim, whom he left in charge as acting Prime Minister. Ten days ago, Dr Mahathir was in Britain, where he announced plans for a Malaysian partnership with a leading UK research company, while this week he was first in Istanbul attending a conference of eight Islamic developing countries and then in Beirut on the first official visit by a Malaysian Prime Minister to Lebanon. Tomorrow, he will arrive in Hungary for talks with his counterpart, Gyula Horn, on bilateral, regional and international issues. He has been only briefly out of the public eye since he began his break abroad by promoting his plan for a Multi-media Super Corridor at a conference in Britain, and has been making prime ministerial statements from foreign capitals at regular intervals. He even 'attended' a meeting of the supreme council of the United Malays National Organisation, which he heads, by a video-conferencing link from London. All of this has served largely to put to rest speculation that his long break from the daily office routine meant that he was planning to slow down and take a back seat to Mr Anwar.