AFTER a shopping binge the likes of which Hong Kong hasn't seen since Imelda Marcos was at her prime, The Great Redeemer (aka President Mobutu Sese Seko of Zaire) and his huge entourage flew out by private plane yesterday. But it wasn't just the shopkeepers who were rubbing their palms and smiling. The Mobutu clan - who were spread across three luxury hotels - proved to be generous tippers in the league of Arab sheiks and princes. We know of two instances where $500 tips were proffered, which by our estimates is more than what a Zairean government worker earns in a month - when he gets paid, that is. Routinely referred to as a tyrant by the international media, Mobutu couldn't have been more happy with the VVVIP treatment he was accorded by the Hong Kong Government. The Governor's Daimler was at his disposal - which must have been something of a let down for Mobutu when compared with the luxurious limousines in his fleet back home. And since Chris and Lavender Patten were out of town, the gubernatorial mansion was probably offered to The Great Redeemer as well. But since he's not given to living in small houses he chose the Regent's vast presidential floor instead. Nonetheless, elements of the Royal Hong Kong Police were dutifully ever-present to ensure that nothing, but nothing, got in the way of his enjoyment. According to our sources, Mobutu and company were originally scheduled to depart after two days, but extended their stay. We've heard certain unkind people suggesting that Mobutu et al decided to stay on longer only because the World Bank was picking up the tab. What an unworthy thought.