For anyone who isn't aware of the story here it is ...
http://www.bbc.co.uk/news/uk-england-wiltshire-23867760

I can't see what objection there could be if it is on private land and yet, and yet, it just doesn't feel right to me. Of course what happens to your remains after death is the concern of others - my general understanding about the people who built long barrows is that they believed in the After Life. Most people today do not.
It feels gimmicky - sorry to be a killjoy (if that's possible in this scenario).