I see that the previous expert has opted out. I will try to help you.
If you want to make the whole of the boundary from gates, you can do. However, having the gate and using it 2 different things.
Even if the gate opened out onto a footpath onto the highway are some of the land, you would need the consent of whoever owns that land to be able to use the access in anything other than an emergency. Even in an emergency, if you use the gate to exit the property and do so over adjoining land, it is still trespass but it would be actionable because you have caused any damage.
If you don’t use this for any other purpose than in an emergency, then the neighbours have no grounds for objection although it doesn’t stop them raising the issue and making the noises which they are doing. They can’t actually do anything about it although they can stop you going on to their land if any work is needed to facilitate the placement of the gate.
They cannot stop you going on to their land and the court would grant you permission if you needed to access their land for any work required to preserve and maintain your property but that does not extend to doing new work or improvements or modifications.
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