STANDING by the lobby of the Grand Hyatt the other night we spotted Governor Chris Patten and tycoon Dickson Poon chatting animatedly like two long lost friends as they passed by. Accompanied by their wives, Lavender and Pearl, they were heading for the elegant Grand Salon where Dickson was hosting a private dinner for the Pattens. Also joining Dickson at the round table were taipans Peter Sutch and Simon Murray - so much for the talk being put around that the big players in the business scene steer clear of the Governor because they see his political reforms as bad news. The dinner with Dickson & Co - and we hope we haven't blown young Mr Poon's chances of being invited to be a Hongkong adviser to Beijing! - is, according to a Government House source, one of frequent private social gatherings Mr Patten enjoys away from his official residence with leading business and political figures. For Lavender, too, informal occasions such as these provide a break in her busy official role as First Lady - and what a pleasant change she makes from her painfully stuffy predecessors. She was at it again yesterday at the India Room of the Hilton attending a Friends of the Earth function where, since she has probably the largest private garden in Hongkong, she was presented with a seedling of a chestnut oak. ''Now that I know what size it is, I'll have a chat with the gardener and find a suitable place for it,'' she said. As we left the India Room we noticed a closed door meeting was going on in an adjoining function room with a brass notice outside announcing ''Christmas Meeting''. So, just a gentle reminder, folks, there are only 218 shopping days left to Christmas.