They’ve built some new houses on the other side of the six-foot fence which runs for 50 yards down the side of our garden. Now the developers have put up their own fence, which is about six inches from our own, and means we can’t get to the other side to maintain it.
You could take your own fence down. If you do this I calculate that the developers will have “given” you an extra 25 square feet of garden! They are entitled to put up their own fence on their own land even if it duplicates an existing fence. You had no automatic right to go onto the neighbouring property to maintain the other side of your fence anyway. Of course the current situation is a nuisance but try to look on the bright side and enjoy the extra bit of land.