It's not your house, the owner could have ripped the plants out the second they got the keys back. They will always be exactly that, memories. It was never your house, you would never see them again.
I work at a plant wholesalers and I can tell you your estimate of how much it would cost to replace (we get contacted often by insurance companies for such things) are way ott. I saw the pics and most of those plants we would throw out as not worth selling. Indeed you were given some of them because they couldn't be sold.
I'm just glad the guy actually got paid for the job he did. You are wasting yours and the tribunals time with this case. You were in the wrong here, nobody else.