Here we are again! We persevere. I am not one of those who believes that everything will be fine and British pragmatism will win. I see what is going on in the world: Trump, Bolsonaro, Salvini, Orban, Putin, Johnson… Brexit was the starting point. The rest you know
You can find more info here:
https://www.peoples-vote.uk/let_us_be_heard#why
I have been at the previous marches for Europe and had a great time. I was worried as I thought it was going to be dangerous, but it was great fun. Of course, I’d rather have a nice lunch with some friends and rest in the afternoon as I work hard during the week, but if everyone finds more comfortable things to do then nothing will change and it a year time we will be complaining and maybe say ‹ I wish I had done my part ›… Remember, this country NEEDS YOU! 
I suggest that you have your kit: bottle of water, sandwich/snacks, throat lozenges, umbrella and a willingness to have fun.