Neighbours have had similar problems and no, they could find no means to address this.
My suggestion of mounting an industrial laser on their garage and dealing with the issue from a distance was not well received.
Dick Roche, linked in this stream of consciousness post by his laser like intellect once suggested a 2.0M maximum height for green stuff as part of his Environment Minister incarnation.
As you can imagine this would not work well in areas where the trees were 100-years oaks and possibly protected under the development plan.
Also there are issues with visual amenity which trees, for all their problems, undoubtedly contribute towards positively.
Can I ask is this really about a view?
Because if it is you have no chance unless its listed.
If you approach it on an amenity basis, you have no chance under the present laws unless they seek a permission on their site and even then it would be difficult to ensure success.
If you approach it on a safety basis you may have more success, but it may be costly to impose a solution from outside.
Have you approached it on a collaborative basis at all?
Assuming you have not yet "had words" and fallen out, might I suggest talking to your neighbours over time about the costs of keeping trees trimmed, the fears of them falling with the increased windspeeds from global warming and how you as concerned neighbours would go "halvies" with any removal costs?
This, over a period of weeks or months might persuade them to come around to your way of thinking about the problems of the trees.
Money always helps if there is any inclination at all to do this and money might be the root cause of this ongoing problem - tree surgery costs money.
Even if you can hack it back for a few years, you will have scored a point.
FWIW
ONQ.