Hi, I have a Richard Keyt in my family (1st cousin 2x removed) who was son of Leena Keyt who lived in Penang.Leena's mother Constance Keyt is listed on the Colonial office register of deaths "searcher organisation clearing house" (don't know what this means) at 161 Kelawei Road in Penang.This could be your Richard.
Also, I have a W.A. Keyt (Walter Arthur Gerald Keyt) who was the person you have mentioned Jonathan.His wife was Enid Dorothea Carmen Thomasz and they had 3 Eileen, Glencora and Ivy (Alexandra).I have only very little information on this family so would welcome anything you have.
I would love to exchange information as it would help us all. Best wishes, Nikki