It's only a very small area right next to Marble Arch to build the scaffolding, guess you got to give them credit for creativity! And luckily it's not going to last till the summer as it will come down on 9th.
The light show definitely was the best part plus it didn't cost anything as they cancelled all entrance fee. Tbh, Iwouldn't mind paying to see the light show, but not the fake hill!!!!