So long story short. We have recently found out that a neighbour is renting out their property with backs onto ours. Our garden ends in woodland. Unbeknownst to us they have fenced off part of our tree lined area and included it in the parcel of land they are renting out as their property. So they are renting out their house and their garden but including a chunk of our garden as part of the deal!! What should I do?! I’m fuming.