From their Facebook:
"💀 🌹 To celebrate Day of the Dead we're giving away a FREE BURRITO voucher to any amigo who downloads our app and joins Los Locos this weekend! 🌹💀 Any new members who join this Saturday or Sunday will have a FREE BURRITO voucher waiting for them in their app!
Offer valid for new Los Locos members only. Free burrito voucher valid until 17/11/19 and excludes extras such a beef, guacamole or vegan cheese. Cannot be used in conjunction with any other offer or promotions." Mod edit: Users report that in the app the voucher states that it expires 16/11/19.