We previously displayed the parent of the detailed guide in the title context. It looks like we partially built this here: https://github.com/alphagov/government-frontend/pull/134/files#diff-7b9336debb8e95427b6577b4d6a75d0eR29. def context isn't used anywhere.
We added the breadcrumbs to the page, which alleviates the problem.
We should either put the context back or remove the context method.