Household debt levels are NOT a hangover form the GFC. They have been increasing rapidly since 2012. A large part of this is student debt, but that is not the whole story.
This TUC/UNISON report estimates that 3.2 million households can be classified as overindebted. Extreme overindebtedness rose to 9% (1.6m) of households in 2015.
Real wages have declined by 10.4% since 2007. The rise in overindebtedness in households WITH employment has risen rapidly. The Guardian reports here