Hi, I have no data about Holyhead/Anglesey deaths at the moment but found the following birth and marriage registrations for the Lydon family on Anglesey.
Births:
LYDON Joseph Ellis, son of Joseph & Ellen MANSON - 6 Apr 1909 - Holyhead
LYNDON (mis-transcribed?) Isabella Manson, dau of Joseph & Ellen MANSON - 18 Feb 1908 - Holyhead
LYDON William Manson, son of Joseph & Ellen MANSON - 4 Feb 1907 - Holyhead
Marriage:
LYDON Christina Manson, 26, of Walthew Avenue, Holyhead; dau of Joseph LYDON (Lieutenant RN) married MASON George, 23, an accountant's clerk of Havana House, Bangor, son of Hugh MASON (cotton operative) on 1 Nov 1932 at St. Seiriol's Church, Holyhead. Both fathers deceased.
You can find the Lydon/Lyndon birth registrations on North Wales BMD