You stated it as a general proposition, so it's hard to disagree. I guess I could also note that on a very concrete promise it would seem that the electors were perfectly willing to let the government take as long as necessary to meet its Syrian refugee total, for example. There was no particular requirement that the total be met within what proved to be an unrealistic deadline. I think that's true in this case as well. To deliver on the promise of abolition of an established electoral formula in the space of one Parliament, particularly when the machinery doesn't get rolling until the spring, strikes me as a stretch. Probably the only administratively possible form of change would be to the ballot—
On August 31st, 2016. See this statement in context.