Originally Posted by Jalinth

If the one way "long haul" is intercontinental, then you are running into the fairly standard problem of not having access to the cheaper fare buckets. Could you provide us the flight itself (YYZ-LHR, or whatever the routing happens to be). The pre/post July 15 could be due in part to ongoing fare sales in the early summer but the routing really matters.

One other suggestion might be buying a round trip and just throwing away the return. Sometimes can be worth a considerable savings