Yes, but he says he took photographs himself (in March 2014) and he would have to look at those?
I have some I took in August 2013 which shows there were no plants, and I also took some last Thursday showing no plants. His property is rented out and it was the tenants father who removed the plants. However, it would appear they are denying this, but I only have the landlords word for that.
We haven't spoken since he said he would look at his own photographs. The plants were removed prior to August 2013 and I don't believe they would have had much value. He was going to pay £600 towards the cost of rebuilding the section of the wall which was damaged by the tree. We had been quoted £1,200 for that section. We also got quotes to replace the whole wall as it had been up for a long time, but we simply couldn't afford it, so in the end we decided to have a fence erected. The cost of the whole fence was £3,500, but clearly we didn't expect him to pay for it all.
Thank you for your advice. Just to clarify though, when I wrote to him confirming his agreement to pay a contribution, we had not agreed an actual amount. My letter to him, dated the 3rd May 2013, said "you have offered financial assistance with the rebuilding of the wall, to be agreed by both parties". Would that be sufficient proof of his intention to pay?