Erection of garden room and increase in boundary treatment height to 2.5m

Have current Hawthorn tree removed. Several parts of trunk leaning further and further towards the house. Grows substantially over the boundary where new houses are going to be built. Tree originally planted at higher level to the property which requires a wall surrounding It to maintain levels and root system, this wall continues to crack and will soon fall down. Repairing and rebuilding the wall becomes expensive. Obviously if permission is granted and removing the tree will cause any damage to the property then I will not proceed Replant several trees along the boundary line species to be decided. Happy to take any advice or recommendations

Erect a boundary fence, part 1.8m high and part 1m high. Fence to be set back 0.3m from path