I've added an important step here that takes us away from the happy path and towards real performance issues. As time progresses using this solution, more of these steps may be needed. The performance test analyst must keep an eye on this and adjust his models and solutions for each particular project.
Here, I have added a method to check for text in responses and report results back up to Jenkins. It is recommended that you check for text as far down the response as possible but that text must be unique to the response coming back correctly i.e. don't just check for '</body>' (!)
The assertion-check.sh script will then count the true and false assertions and report back to Jenkins based on a percentage pass limit that you can set.
To use this feature, add a response assertion and an assertion results listener: