At first it seemed like a straight forward case of violent armed home robbery perhaps targeted cos of the expensive range rover in the drive way? or racially targeted because they are asian/indian/sikh?
But when you look at the video again you can see the first guy using keys to get into the house and also one of the attackers is a woman who has masked but you can tell with her legs and body frame its a female. So it seems like a targeted attack someone who knows this family personally perhaps ex-partner/ex-wife maybe? Or ex-tenets targeting the landlord......Just a theory and observation