Hello Kathleen

Col has given you birth of Geoffrey/Jeffrey. The Manx BMD index for marriages has been down since March for updating, so cant check for Marriage. Brian Lawsons Marriage index only goes to 1923. No marriage on UK BMD.
Very hard to track people in this later period.
The following births registered in Castletown are possible siblings;
1935 Basil
1937 Anthony Eden Buried 1972
1939 Kenneth
1940 Juan Athol
1941 Robert
1944 Neville
1947 Ian
1947 Wendy

All of the above initials are on Manx Telecom White pages excepting Anthony and Wendy, Wendy of course may have married.

Cheers
David