A link is not the right control to use, since it is intended to fetch a resource not invoke an action on the page. Whilst this is likely a thing that upsets developers more than users, it is relevant here because the link inside heading design pattern is already in common use for exactly this purpose - such as on blog homepages, retail product results pages etc.
It will be interesting to see if this performs better than Test Case 2 for speech recognition users as the control looks like a link (blue text with an underline).
Test case 3: https://govuk-accessibility-sandbox.herokuapp.com/patterns/accordion-with-descriptions/
A link is not the right control to use, since it is intended to fetch a resource not invoke an action on the page. Whilst this is likely a thing that upsets developers more than users, it is relevant here because the link inside heading design pattern is already in common use for exactly this purpose - such as on blog homepages, retail product results pages etc.