I suppose the major point here is .. what would happen to the ditch if council don't maintain it.. i.e would you clear it out (a horrid job). either way it needs maintaining and if there;s a fence and deep ditch with any appreciable distance between them then a small digger won't reach without tipping.
Aside from all that I strongly promote planting fruit and nut trees along field edges - forget the wild natural stuff.. stuff you can eat and give away - plums wallnuts, sweet chestnut, apples, etc