WHEN Sir David Ford was Hong Kong's Commissioner in London in 1980-81, most of the Chinese people he knew were in the restaurant business. This time, life for both his Chinese contacts and the Commissioner himself is very different. ''The second generation are in the professions. So there has been quite a change within these communities,'' Sir David said. It is a change, accompanied by efforts to enrol those people in Hong Kong organisations and use them as ambassadors for the territory, that illustrates the dilemma confronting Sir David in his new post: ''The question now is where the focus of the Hong Kong Government Office should be, whether more business-focused or cultural.'' It is a question he is pondering as he settles into the Government's Grafton Street office, just off Bond Street, which is one of three offices occupied in London by the Hong Kong Tourist Authority, the Hong Kong Trade Development Council and the Government. But that may change, Sir David says: ''It makes sense to have one building, one Hong Kong House.'' That emphasis on making the best use of time and resources means his office is now targeting two key areas: ''On people doing business with Hong Kong, investing, setting up offices, economically involved, trading. ''They are the most likely to understand the influence of Hong Kong to realise its potential. This is much more so now than in the early 1980s. ''Twinned to that is how we deal with the opinion-formers, like the media and politicians. As we come closer to 1997 this becomes a very sensitive story, more and more in the headlines,'' he said. ''It is very important for people to understand the changes involved and how Hong Kong will continue to prosper. That is a never-ending educative process. It is important not to have a scattergun effect as we only have so much resources.'' And time is of the essence, Sir David warns. ''The time scale is short so our focus must be more direct.'' That means a Hong Kong festival such as the one held last summer in London's Battersea Park, which drew 500,000 people in one weekend, is probably not appropriate this time, he says. ''Now there is much more known about Hong Kong. Battersea Park saw the softer side of Hong Kong.'' Sir David, 58, is pleased to be back in London for his three-year term - he told his London staff last time he left that he was young enough to return to the job post-Hong Kong - despite finding the crowds and crime make it less comfortable than a decadeago. Aside from being able to retreat to the 250-year-old home in Devon he bought five years ago and converted from two cottages, he is able to play tennis at the smart Chelsea Harbour Club with his two sons and weekends with his daughter, Amanda, a teacher in Exeter. AND he's happy to be living at the Commissioner's Cowley Street residence, near Parliament Square - a ''bargain'', bought from the Church of England for GBP110,000 in 1980. ''That's one of the great things about living in the centre of London that you can't do in Hong Kong. I have found this time coming back to London, both very delightful and frustrating. ''On the plus side is the music and theatres, which are delightful. And it's terrific to be living in the centre of Westminster. But travelling is frustrating, especially outside London. I made two trips up north recently and it took two hours to travel 30 kilometres. Hong Kong traffic is heaven compared to England's motorways.'' When his posting expires in 1996, Sir David wants to retain his Hong Kong connections. By then he may feel ready - and morally able - to go into business. ''After government I feel that you should not take on commercial work where you make use of your connections. I feel very strongly about that. It's part of the loyalty test, part of being a public servant. ''That was part of the question of why I was happy to continue in public service and not go into the private sector. ''I've certainly had plenty of offers. I would feel quite uncomfortable about accepting them. That doesn't mean to say that I may not go into business at some time. It depends how I feel in three years' time.'' Last time Sir David was in the London hot-seat his main task was to have the best possible result for Hong Kong enshrined in the British Nationality Act. He admits that didn't happen. ''At the end, when we saw what the new Act was, we were disappointed at the outcome. The whole concept of the Nationality Act, which was to make clear that citizenship does not necessarily go with right of abode in the UK, this was something we were, we are, very uncomfortable about.'' It wasn't any easy time. The issue was politically charged - it still is, and Hong Kong is a sensitive subject, Sir David says. ''As a domestic policy in the UK it is a very big issue. Looking at the problem from Hong Kong is very difficult for some.'' For Sir David, the only Commissioner to hold the post twice, the next few months mean travelling throughout the UK, renewing his links with its Chinese communities and meeting their new members. His Chinese New Year included celebrations in Manchester and Scotland, a visit to the Chinatown Community Centre's exhibition, a London Chinatown Chinese Association dinner and visits to Chinese language schools. But didn't include meetings with the Chinese Embassy staff, although Sir David says he may run into them at social functions. As to what post-1997 holds for his office, he's unsure, but says part of his job is to prepare for that handover: ''There will be some head office. Whether he will be called the Commissioner or not who can say? ''My job ends for me in 1996. That we are moving towards being an economic and trade office is already on record. We have to look at how to prepare for becoming an economic and trade office by 1997.''