Bells are beginning to ring a bit.. well, just a gentle tinkle! I don't recall any Dash-7 going out low-level, and thereby leaving CAS. However, such aircraft were not subject to noise abatement so, with agreement from the TMA, we'd often turn them onto a heading to get them clear out of the way - usually around 250, depending on wind, was enough. They'd then continue to climb out on that heading whilst we launched a few north and westbound departures to use up a few minutes until it was safe to continue with SFD and DVR SIDs.