The name "Fernandu" is actually spelt with an "O" at the end as FERNANDO. DE SILVA also has similar origins and extremely common amongst, both, Buddhist and converted Christians all over the Island. Their origin is supposed to be Portuguese. Herewith are some search results that I was able to obtain that may interest you:-
Family #3066 (Sinhalese Family Page) 1Veerthamulla Gamage Don Fransiscu Senaratne Kumarapperumal b:1737 in Kahawatte in the Giruwe Pattu, bp:5-Feb-1758 + Fransina Jasenthu Greru
…2Dona Cornelia/Gajaman Nona b.1758 bp:30-Jul-1959 in Milagiriya (?), d:15-Dec-1814 + TalpeMerenchige , a Lascoryn who later became Gardiye Arachchi who died circa 1782. ……3Juan Alvis
…22nd Spouse of Dona Cornelia/Gajaman Nona: Muhandiram Don GabrielSiriwardene Vijaya Vimalasekera ……3Name Not Known ……3Name Not Known ……3Name Not Known
…2Don Luis Senaratne Perumal Wijerama Kumarasinghe
RAJAPAKSAMRS. D.S. Relict of J.P.A. Jayawardene of Asgiriya, Gampaha; mother of Irangani and Shantha A. Jayawardene (Minu / Dewalapola Ananda Maha Vidyalaya), mother-in-law of H.D.I. Gunawardene and Walter Kumarasinghe; grandmother of Sumedha, Dhammika, Lakshman Kariyawasam, Lal Ranatunga, Chamani, Samantha and Dilisha, sister of late D.Y. Rajapaksa and of D.U. Rajapaksa of Henegama and of late Mrs. D.C. Dissanayaka of Wataddara and of P.J. Rajapaksa of Kottamulla, expired. Cremation at Asgiriya General Cemetery at 3.30 p.m. on Saturday 5th June. No flowres please by request. 145, Asgiriya, Gampaha. (June 5, 1999)
BIBILECHARLES WIMALA. Beloved husband of Chitra, loving father of Waruni and Supun (A.F. Jones), father-in-law of Anura (Air Lanka) and Deepani (Odel), brother of late Senaka, Suja, Ananda, Chandra and Cuda, expired. Cortege leaves residence at 9.30 a.m. on Saturday 5th June for Cremation at Badulla Cemetery at 10 a.m. No.