Anything which crosses the boundary is trespass unless there is a specific right of over hang. If there is no specific right in the deeds to the property the neighbour could have acquired a right if over hang if the the dish and aerial have been there for at least 20 years, this is a prescriptive right.
It is your neighbour who must prove they have the right as opposed to you proving that they do not.
You can write to the neighbour to state the dish and aerial over hang which is trespass and must be removed. If the neighbour refuses you may have to get a court order.
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