The Hood Aerodrome footage was filmed in April 2019.
So... back in 2019 there was an almost finished, rotary powered and with authentic structure D.H.2 and no one knew about it? 
No no no no no. There apparently were (are) two. And some people knew, just not any who could say so! I'm not including myself in that, there's little worse in any hobby than "I know something you don't know" - if you know but can't say, then don't!
What did YOU spot? On my first watch I caught:
- the aforementioned DH.2 5964
- Morane N under construction and referenced
- Maurice Farman with the weirdest noseart I’ve ever seen
- Albatros D.V/a
- an original Sopwith 1 1/2 Strutter
- Fokker Eindecker getting bagged
- Sopwith Snipe