I am of the opinion that Mr. Burchell WILL turn out to be the uncle of Mr. Thornhill (as some others here have also postulated). If that is the case, I don't get him. Everyone in the countryside talks about how WONDERFUL Mr. Burchell is and how he is beloved by everyone in the countryside. And yet, he is aware of what a MONSTER Mr. Thornhill is - seducing and ruining numerous young ladies. (As evidenced by his unheeded warnings to Olivia.)

IF he is, indeed, the uncle of Mr. Thornhill WHY would he give him the money with which to ruin other people's lives? Even if Mr. Burchell cuts off his money at some future point in the novel and brings Mr. Thornhill to his well-deserved ruin, it will not make up for the numerous women and families that Mr. Thornhill has destroyed.