MORE changes at Metro, where two long-term (by their standards) staffers have decided to take a bow. Business chief Teymour Nabili and anchor Chris Slaughter are quitting the Hong Kong airwaves. Nabili is heading for Singapore and a job with the Asian Business News television service. Slaughter is off to Tokyo to join the English-language service of national broadcasters NHK. That is good news for Ward Edmonds, who was to have lost his job when he returned from a four-month sabbatical, but has been spared the slaughter, as it were. TUESDAY brings the monthly invasion of the Fringe Club by Hong Kong's ceilidh crew. Folk night at the Fringe brings Folk Society regulars like Atlantic Bridge, Ian Geekie, Richie Weintraub and Brian Lawless to the stage. Visiting musicians also add to a party air which often extends beyond the performances in the theatre to late-night jams at the bar. Tickets cost $40 for non-members, $25 for Folk Society members. LATER in the we ek, The Shadowboxers take to the same stage to play similar music. The Saturday night event is described as Shadowboxers Unhinged (''if Clapton and Young can do it, why can't we?'') and fans can expect laughter and no mean musical ability from stalwarts Neil Harris and Gerard Tannam. Tickets are $50 for non-Fringe members and $40 for members.