Little Mix are not a global group. The top 5 music markets in the world are: USA > Japan > Germany > UK > France. Little Mix are only successful in 1. Here is the chart run for LM5:

France - 55 > 146 > OUT
Germany - 22 > 87 > OUT
Japan - 60 > 96 > OUT
USA - 40 > 156 > OUT

They've never had a certified album in any of those countries. If you like the group fine, but don't delude yourself into thinking they are global based on social media and the fact they performed in an exhibition hall in Belgium.