Term start and end dates

[wfdd]

Currently, we use the date MPs were sworn in as their term's start date; and the date parliament was dissolved as the end date of the 2011 parliament, and the day before the new MPs were sworn in as the end date of all parliaments prior. This is a discrepancy that needs fixing but we first need to decide what the right way to do this is. To the best of my knowledge, even after parliament is dissolved, MPs may call an extraordinary sitting, so the parliament's dissolution is - at least in part - nominal. I've cursorily flipped through the relevant bits in the Constitution and the election law ([1]) but neither provided any answers.