BP dodgy fuel

While traveling from St Helens to Hobart in my Honda CRV over Easter I filled up with BP premium unleaded, spending about $63. Five minutes later all the malfunction lights came on, suggesting there were problems with the Braking system and stability control and although the car was still safe to drive I should take it to my dealer as soon as possible. I drove on until the fuel gauge was showing empty, but the malfunction lights were still flashing, so I pulled over and called the RAC. They could not diagnose the problem, but escorted me to a service station to fill up. The car took very little petrol so it was a fault with the fuel gauge. We decided it would be safe to drive on to Hobart. The next morning the car went into the garage and was there for four days at a cost of over $600 because they were unable to diagnose the problem. On the fourth day they eventually diagnosed that there was water in the petrol and said they had taken at least four litres out of the tank. The fuel system is now damaged and apparently the fuel tank is corroded due to the presence of water. I contacted BP who after 10 days replied that they were unable to substantiate my claim that the damage was due to contaminated fuel and that they had no liability. The garage has a sample of what was taken from my fuel tank. Do you think there is anything I can do to address this injustice?