Ford Falcon 2013: Can't fill LPG on hot day

I brought a Ford Falcon XR6 EcoLPI in 2013 and was never told there were any issues with the gas tank. In early 2014 we encountered a problem filling the gas tank on a hot day — 44 degrees. The service station attendant told us that on hot days we wouldn't be able to fill the tank as the gas expands. We waited over an hour for the tank to cool and then threw water on the tank under the car to cool it. Recently I stopped at Gundagai to fill the tank as I was nearly on empty. It was 5.30pm and overcast, the dash readout was 28 degrees and I had only been driving for four hours — and I still couldn't refill. It's been so hot since the new year that we haven't been able to fill it so it has sat in our garage. Ford Australia says it's aware of the problem, it's covered in the owner's manual and I should have been aware of this. But I haven't found anything in the manual.