Please excuse me jumping in when you asked someone else a question but I have just altered my insurance to cover accidents (after the big tank sprung a leak!)
For the small tank, 3ft, we didnt need to take out any extra insurance and it is covered under the standard insurance, the big tank 6ft, wasnt covered on the grounds that the value to be replaced is over £1000 if you include everything... apparently, anything over a £1000 has to be added on to the insurance as an extra premium hence ours is now valued at £999.99
As for the carpet, thats only covered if we take out accidental cover with an added liability cover which put a lot more on the premium
But, if by chance, I dropped a tin of paint all over the carpet and needed to claim for a new one.. that would be covered by the basic accidental damabe cover we have...
May or may not help you but, thats my experience! would be good to hear others to see if I need to find a new insurer!
Donna