It sounds like you've made the best of a bad situation. I agree with the others that you could have short-circuited this issue by storing your dinghy differently to begin with, but I think it was a pretty gray area and I'm not sure I would have been any wiser myself :P
I cringed when I heard you had written a letter of apology, but then I remembered that your choices are basically try to patch things up with your landlord or go and find new moorage. You can win a legal battle against him, but then the animosity will never end.
1972 Catalina 27