Personally I think it should. If it had been left where it was, the timbers wouldn't exist in 20 years. Exposed bronze age timber isn't going to last many North Sea winters. And then all we have of seahenge, is a stretch of empty beach.

So it wouldn't be there either way, might as well save it and use it to teach people about the culture that built it. The timbers were supposed to be (eventually) heading to Kings Lynn last I heard and will give the locals an invaluable look at what their ancestors were doing many thousand years ago.

Not to mention the knowledge gained by pure research on it.