If the hedge is straddling the boundary, and it’s a party hedge, they are quite entitled to cut it right back to the trunk although they must not kill the tree. They can only reduce the height of it with your consent .
If by cutting the branches back, it exposes gaps in the hedge, that is unfortunate I’m sorry to say although if they have done this in order to erect a fence, that will remedy what was previously the removal of your privacy.
Although it may have also removed an element of security, that is not the neighbours responsibility I’m sorry to say.
In respect of the part which he has cut down to the ground, although that is criminal damage, the police will not be interested although you are entitled to have it reinstated and to take the neighbour to court to get that done if necessary. Check your house insurance to see if you have legal expenses cover that would pay for the cost of that.
You say that there is no use talking to the neighbour is all you will get is abuse and therefore, you cannot beat the neighbour with a stick until she plays the game and your only remedy is either court or the housing association. You say that you have tried to contact the housing association but they haven’t responded. I don’t whether you’ve done that on the telephone but if you have, I would suggest you put that in writing because whilst it’s easy for them to ignore a telephone call, it’s not easy for them to ignore a letter.
Can I clarify anything else for you?
I’m happy to answer any specific points arising from this.
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