I'm hoping to check my understanding of UK law regarding flight compensation rules where a flight has been cancelled.

I was due to fly Edinburgh-Toronto-Ottawa leaving 9am June 6th, on Air Canada. Four days before the flight, AC cancelled that flight and rebooked me at 6am on the same day, flying Edinburgh-Frankfurt-Toronto-Ottawa. Because I left Edinburgh three hours earlier, I arrived in Ottawa at roughly the same time as the original itinerary.

As I understand the UK rules, I am entitled to £260 of compensation, since the trip was over 3500km and the departure time on my replacement flight was more than one hour earlier than the departure time of the flight that was cancelled (and the cancellation happened less than 7 days in advance). Air Canada is however insisting that no compensation is owed on the grounds that my arrival in Ottawa was not delayed. I've consulted multiple websites (including the UK Civil Aviation Authority, screenshot below) that seem to confirm my reading of the UK law, but AC keeps insisting I'm wrong. Am I making some silly mistake here and misreading the UK rules or do they indeed entitle me to £260 of compensation?

For what it's worth I wouldn't fuss about this except the 6am flight was a major pain to catch for logistical reasons I won't go into. Plus AC has a very bad reputation in Canada for lying about compensation claims so if that's happening here I don't want them to get away with it.

thanks.