I suggest you ask Greg to make you a receipt for what the tank would cost normal retail, just for your records, not what it actually cost.
When our tank cracked and flooded the lounge, dining room, kitchen and had started creeping up the hall, AMI was very good to us. They would not cover the damage done, as it was not considered a "normal water supply" fault but did suggest we get the dearest quote possible to replace the tank then use the excess to help pay for lifting the carpet, drying it out, and re-laying.
We have since changed our contents policy to make sure it includes aquarium breakage and damage caused by same.