Final answer:
The phrase suggests that after completing an action involving Danny, a celebratory quickstep can be heard, indicating a transition or festive response.
Step-by-step explanation:
The phrase "For they're done with Danny you can 'ear the quickstep play" likely references a situation where a character, Danny, has completed some sort of action or event, and as a consequence, celebratory or onward-moving music, specifically a quickstep, can be heard playing. The quickstep is a lively dance associated with fast-paced movement and energy, which suggests that the events concerning Danny have reached a conclusion that prompts a musical, possibly festive, response. This interpretation fits within the broader context of narrative or theatrical performance, where music often underscores key moments or transitions.