In 2006, EBS and all the other lenders were handing out tracker mortgages, so there wasn't any reason for them to intentionally take you off your tracker. They did not appreciate the value of trackers, so it would have been difficult for them to warn you that you would lose your tracker.
This is the sort of issue which will only be determined by the High Court unless the Central Bank convinces AIB to put those affected on trackers.
EBS would argue that "the applicable variable rate" was clearly not intended to refer to a tracker.
You would argue that a tracker is a type of variable rate.
Brendan