Sorry I've been slow to report back on this. After a lot of time on the phone they refused to put me on a direct flight with a different carrier. My options were changing days or flying via Panama (5 1/2 hour trip instead of 1 1/2). I shuffled my plans and switched days as I'm already doing so much flying on the trip I couldn't face the connecting flight.

Not sure if I should be happy with this or not really? As cancelling a flight with 1 1/2 months to go must be a relatively rare event I don't see why they couldn't put me on another carrier to keep me happy. They have basically changed their schedule to save money and cost me (hotel bookings etc).

If it was further in advance it wouldn't have been as much of an issue because I could cancel and re-book on another carrier, but being close to the ravel date means their prices have all gone up significantly.

It's not the end of the world, but is one of those frustrating situations