OUTGOING Chief Secretary Sir David Ford yesterday defended his three-year contract for his new job as Hong Kong's London Commissioner. ''It is a matter for the Government, of course, how they can best make use of my services. I am glad that most people in the community think it is a good way of making use of David Ford and I'm certainly very happy to hear that too,'' he said. ''I think that I do have some experience which I can offer.'' The contract will see Sir David serve beyond the maximum retirement age of 60.