SORRY about this, but if one more person mentions Millfield School in my presence I will not be held responsible for my actions. It seems as is if this town is being handed over to Millfieldiens past and present and an assortment of parents. And there is no escape. Faxes and telephone calls have been pouring into Keeping Posted about this academy of learning in southern England and you cannot switch the radio on without hearing something or other about the ''OMs''. The gathering of the local Millfield clan - which includes business tycoons Stanley Ho and Henry Fok, who sent their children there - has been brought about by the arrival in Hongkong of headmaster Christopher Martin and, more importantly, Joyce Meyer, the widow of the revered founder of Millfield School, ''Boss'' Meyer. Among the activities being planned over the next week by the OMs - Timothy Fok among them - is a ''Sizzling Sichuan Prawns In Cider Sauce'' affair which, no doubt, should remind them all of umpteen school dinners - if not of Somerset's traditional tipple. By all accounts ''Boss'' Meyer was quite a character, with an egalitarian approach to private education which earned him much kudos. It is said that the British statesman Earl Atlee once told Meyer that he sent his son to Millfield ''because of my socialist principles''. (Although one suspects that the motives of Messrs Ho and Fok in sending their offspring there were quite different.) If, for some strange reason, any OMs out there have missed out on the happenings they can contact Martin Craigs (phone 849 7083). But be warned that school ties must be worn at the Prawns & Cider reunion.