Hello Alison.
Depending on status of wealth/social standing of the Wright family 1914 to say 1925 will give an idea as to if Sarah's coffin made the long journey North from S London to Skipton being an expensive undertake to the funeral cost and if so ! chances is high there would be a headstone on her grave in Skipton.
Your quest to find Isaac's widow Sarah Wright nee Smith death year and where. You mention her daughter who lived in London and Sarah was believed to be alive circa early 1920's in South London, if your can elaborate on this thread further, all you know of the daughters life, like her residence area of London and age of Sarah at her marriage to Isaac with year of marriage (1868 ? from your other threads)
If the daughter and Sarah are together on the electoral registers address S London early 1920's - then the year Sarah disappears off the Electoral Register (E R) ? will give you a starting point. (reason for a disappearance off a E R - could be death or moved into a local care home.)
The more info you give ? the more chance RC members can research
for a result of Sarah's demise year.
(To give you an idea ! Say Sarah died in Lambeth London, and by chance, an enthusiastic to help member of RC could just happen live near Lambeth Library where the 1920's Lambeth ER's are kept.)