If it was me, i would apologise for leaving the gate open (if i did?) even if the guy is a pr..k. I would be firm and explain it could have been the wind as its never happened before! I would then say its a shame to lose you after you being on with me for 10 yrs, but if you change your mind just give me a shout. However there is always the chance he just wants to cancel and is using that as a excuse?
OR
If you just don't like the fella, or the situation, then convince him that there is nothing around the back worth robbing anyway
, and then just F it off.
But by the sound of him, anticipate he will probably slag u to the other neighbours anyhow? Good Luck
I would just apologise for leaving the gate open. I wouldn't suggest another reason, eg. the wind. I would then use your suggestion. Its a shame to lose you after you being on with me for 10 yrs, but if you change your mind just give me a shout.
Then leave it at that.