This is a piece of advise for my mother who is currently going through lots of old paperwork.
Back in 1990, she and my grandfather bought a house between them, both named on the mortgage with the Nationwide. Both her income and his pensions (he was 70 at the time) were used to get the mortgage.
Both had to have Decreasing Term Mortgage insurance linked to the property in the event of either of them dying as it would clear the mortgage.
In 1992 my grandfather died and whilst dealing with his affairs, my mother (and I as a teenager) visited our local NW branc