Please contact Dr Malcolm Jansze in Colombo. You may e-mail him at firstname.lastname@example.org and arrange to meet him when you are there. He has a wealth of knowledge and records on Sri Lanka Burgher Genealogy.
You may also contact Ms Cherise Pereira at The Dutch Burgher Union Headquarters at Bullers Road, Colombo 4. Her e-mail addy is email@example.com