Don't rely on specific classes for subsections.

By genericising the cucumber feature to just 'click on <x>' rather than 'click on the <x> subsection' we don't lose any clarity, but we remove reliance on specific classes (i.e. the previous 'within' block to detect where on the page to click)

In a happy coincidence, there's only a single link on the employment income manuals page with "EIM00500" in it.