"Stonehenge stuff looked a bit shady though ..."

Agreed. The whole precept seemed based around the fact of two 'windows' created from the central Trilithon.

If that's the case, what are the other Trilithons doing there? Why bother with them?

I was impressed with the Newgrange shots though. I hadn't quite got a grip on the scale of the thing from books I've read. Seeing the guy standing there put the size into perspective!