Good finds, bbart!
School admission record at Tredegar Wharf School for Maude Emily Day dob 19 Dec 1885 - admitted 22 May 1894, parent Emily Day, address 79 Lewis Street, previous school St Paul's Cardiff. Left the district 17 Aug 1894.
Parish marriage 16 Nov 1907 Parish church of Canton, Cardiff
Herbert Sturley 22 bach Lithographer 29 Cumberland Street father Henry Sturley carpenter
Maud Emily Day 22 spinster 29 Cumberland St father Henry Day fishmonger
witnesses Walter John Hallett & Beatrice Day
Death reg Maud Emily Sturley dec qtr 1971 Bristol vol 7b pg 48 dob 19 Dec 1884
Possible marriage Beatrice Day jun qtr 1910 Newport vol 11a pg 337 to Walter John Hallett or Thomas John A Thompson
Beatrice Hallett is shown as a widow on the 1911 census
https://www.familysearch.org/ark:/61903/1:1:X7P8-DY3However Walter J & Beatrice are together on the 1939 register, her dob 1 Nov 1888
Death reg sept qtr 1969 Newport vol 8c pg 863 dob 1 Nov 1888
Probate index shows her death as 6 Sept 1869 of 43 Fields Road, Newport. Same index, Walter John Hallett died 28 Aug 1956 of 38 Fields Road, administration to Beatrice Hallett, widow.
Register office isn't unusual if one of other of the parties was non-conformist.
Hope this fills a few gaps.