Ask an Property Solicitor. Get an Answer ASAP.
From what I remember I believe that I simply said that I would look into it, at that time no conditions were set and nothing was written down.
When he agreed to paying for the tree removal and replacements I asked him to write down his intention then but he refused saying that would make it legal and he didn't want that so it was a real surprise when he started threatening legal action.
Thank you for your reply
He has said that he has made notes on each time we have spoken so I guess these are what he would try and use as a record for me agreeing to remove the tree, though I really do not remember agreeing to taking it down at that point. Are his own written notes useable against me?!
There were definitely no conditions set.