Dispute regarding garden wall with neighbour?

I have the most ugly looking wall running down one side of my garden built using breeze blocks and topped off with glass cube tiles (NICE!!) I recently cleared a load of ivy off my side which was growing all over it and in doing so some of these glass tiles fell off as they werent even fixed on breaking two of them. I have replaced them using two at the very bottom of the wall that is hidden by my neighbours tree and my tree. My neighbour has now had words saying i have taken more than 2 and what i have done looks a mess! Mess isnt the word for my side of the wall. I have bits of cement hanging out and gaps in the walls where it was never made tidy when their son built it before I moved into the property over 11 years ago. The wall is also very unsafe and leans on my side of the garden. My question is 1, Should they be made to make the wall tidy my side? and 2, Can I in anyway make them remove the wall as it is a health and safety risk?