I booked BA Club Glasgow-Chennai via Heathrow. At the time of booking the departure time for the international flight was 08:30. Because it was a tight connection and a January flight (and therefore subject to weather disruption) I elected to fly down the night before and stay in an airport hotel. As the flight was scheduled to land at 01:00 I also booked that night at my destination.

When I came to check in online I learned that the departure time had been changed at some point to 14:00. BA have admitted that they failed to notify me of this change. They have all my contact information and did notify me of a 20 minute change to the domestic flight departure time. Furthermore the original flight details remained on the BA app on my smartphone, my tablet and my wife's smartphone.

Had I been informed of the schedule change I would not have spent a night at an airport hotel and would have taken my chances with an early check in at my destination knowing that if the room was unavailable it was at least daylight. I also took an extra half day's annual leave and had to pay for my dogs to be looked after for an extra night. Am I being greedy expecting more than the offer of a �100 evoucher or 10000 Avios? From my perspective it was the equivalent of a delayed departure of over 5 hours.

This is certainly unfortunate, but I don't think it will fall under EC261 compensation rules for a number of reasons. BA will probably argue that the decision to go the night before was yours alone, since it was prepared to get you there with the (tight) morning connection. Therefore, the change of departure time becomes irrelevant for the sake of hotel, dogs, holiday, etc. Unfortunate, yes, but I suspect that's the position BA will take.

What's potentially interesting, and what you may wish to consider, is whether the later arrival time into Chennai falls under the delayed compensation rules of EC261 (I suspect it does). Here is becomes a question of when the airline informed you (apparently they didn't) so you may wish to fly a claim for a late arrival (€600).

I see you've double posted this in the BA forum, I'll ask a moderator to merge them.

This is cross-posted. You asked the exact same question in the BA thread and with the full facts there, it does appear that there is an EC 261/2004 claim. One of the problems of cross-posting (besides violating FT rules) is that you and other FT users lose the benefit of the entire thread.