TIME was when Francis Gouten (left) and his friends used to spend many a roistering evening at the Plume. Fortified by good food and wine Gouten, now based in Paris with Piaget, had a regular routine. He would stand on top of one particular table (his ''stage'' he called it) and sing, dance and - as the mood beckoned - divest himself of excess clothing. Thus when the Plume underwent a thorough refurbishment, Gouten contacted Regent GM Thomas Axmacher and inquired anxiously as to what was to become of his ''stage''. Axmacher, a good sport, arranged for a piece of the table to be turned into a trophy and presented it to Gouten when he was in town recently. The trophy, we understand, is destined for the Francis Gouten Wild Life Museum.