Thanks for your answers! Last time I cosplayed in London (for a Star Trek Convention, a long time ago), I travelled with my costume: it was the best welcome I ever received from people! I asked about it because in France, cosplaying in not -sometimes- really well accepted, unfortunately...
So I will get dressed at my hotel (as Loki), and so my bf as she has accepted to come with her own cosplay (Harley Quinn).
See u soon!!!