Posted: 21/02/2015 at 14:33
I'm inclined to agree with nin and Welshonion regarding the species you've used. If you were to sell up in a couple of years your neighbour might be faced with someone in your house who didn't care if these leylandii grew to 50ft rather than 5, and then she or her successors in that house would have a big problem.
Particularly as you are in a rural location, why not go for a mix of native shrubs and exotics that don't misbehave? They can be easily manged and don't need to be neat. Plant well back from the fenceline so that you've got room to get round to the back of it for maintenance. Make the actual legal boundary a simple post and wire fence (with mesh to keep your dogs in) but good quality posts which only need to be a metre high. Agree the boundary with the neighbour, both verbally and by letter, to avoid controversy later.