As stated in the question the tree is potentially damaging because its so close to the building. Being on the south side of my garden, If left to grow it could achieve 60ft in height blocking light from my Kitchen and bedroom windows, putting my garden in constant shade and causing massive leaf litter every autumn. It could damage my roof/guttering during high winds and the roots could cause damage to my garden flowerbeds, walls and foundations.
The neighbour was obviously aware when planting the tree that it would overhang my property considerably yet still went ahead. The advised distance from buildings for this kind of tree is 8.5mtrs, twice the distance this one has been planted.
Ideally, I would like the tree removed before it reaches the stage of blocking light entirely or causing damage. I'm also aware that it may affect the value of my property being a potential hazard. The neighbour now has a dog which means I can't take my fence panels out for maintenance for fear of the dog escaping, so reintating their boundary fence would also be beneficial.
According to my neighbours deeds of which I have a copy, they must maintain a boundary fence or wall and mustn't do anything to spoil my enjoyment of my property nor reduce its value. Regarding light, I believe the Prescription act of 1862? states I may have earned the right to light having enjoyed it for over 20yrs before the tree was big enough to block the light.
I've contacted the local authority from whom both our properties were purchased but they aren't interested in private residents disputes, even though the wording of our deeds are basically a contract with them?