THERE'S a juicy story doing the rounds at the BBC's Television Centre in West London (and also featured in the satirical magazine Private Eye, so there must be a modicum of truth in it) concerning Beeb chairman Marmaduke Hussey's recent trip to Hongkong. Apparently Chairman Hussey had a long lunch with a leading Hongkong businessman who has the ear of China's leadership. And over the beef with broccoli in oyster sauce, it was supposedly intimated to Mr Hussey that a brief film montage promoting the finest moments of BBC News carried daily by World Service Television (the Beeb's answer to CNN) - which includes footage of the goings-on at Tiananmen Square in 1989 - could do with a discreet snip of the scissors. Apparently those parabolic devices that sprout from the roofs of the comfortable compounds in Beijing have been zooming this ''offensive'' trailer down to the pampered cadres in their living rooms and, naturally, they are far from happy to have daily reminders of their historical botch. Worse still, they must harbour fears that certain troublesome types elsewhere in town might be able to see it too - and take heart. Word has been put around that no sooner had the BBC boss got back to London than a discreet memo to this effect was sent to World Service Television. But, quite sensibly, they decided to take no notice.