No idea what this is, would have been good if one of the companies filling the tank would have suggested it. To be honest, I just want to move forward and get on with my life, i'm not interested in suing anyone. There are bigger battles to fight
I would claim back off them. I have worked for a fair few letting agencies and some of them took the money answered a few phone calls regarding the property and never carried out inspections or didn't carry out what they promise the people they would do.
These type of people need to be punished financially not you. I would get a few quotes and work out the average then take it to a small claims court you would stand a good chance as they have not carried out their job.
That's just my opinion though over my career I've had so many people try to claim against me for something thats not my fault I think why not.