Presumably you're talking about the McKenna Cup game when referring to the Derry game being called off. Now I'm 100% not defending the GAA, but a few things you were lead to believe (if this is the game you're talking about) were absolutely incorrect. Firstly the game was at Athletic grounds. No one was charged or admitted to the ground before a decision was correctly made to call the game off. The photographer had quite a few pictures of the field on Facebook. You're right though that it should have been done earlier in the day. The only expense incurred was the cost of travel. I've been to Roscommon before when a game was called off. It happens.
No refunds were due as nobody had paid anything. I'm 100% sure of that as I was there waiting and the gate men never opened.
Other games were called off and spectators were charged and admitted before being told the game was off. On the official GAA website they had posted that tickets could be used at the refixed game or transferred to someone else to use. If it didn't suit they could be brought back to the point of purchase for a refund or it could be organised by any club or county board. Seems in this case they might have actually made an effort to do the right thing.
You're also 100% correct when you mention redress under law. It's covered under the supply of goods or services. If it's not supplied then a full refund is required if an alternative is not provided or suitable. Same as concert tickets for example, in the case of a postponement.
We have to stop pussy footing around and call it as it is. Ripping people off is ripping people off. I just hope they're reforming. I've a vested interest as a few years ago, a league game against Dublin in Crossmaglen was called off and refixed. I was in Rome for the new date and no chance a refund. I've never let it go!