I know parents who moved "average" children there from other local preps because they were worried about not getting Hampton/LEH. I think this is pretty much their target market. Everyone I know who has children there is very pleased with it, for younger children you have to accept it is not a prep, they will not be preparing you to move at 11 or 13, it is a straight through school. Parents with children in older years Y8+ say it is academically vigorous, and these are "demanding" parents who have the siblings at LEH and Hampton. Quite a number of boys went from Newland House at Y6 last year. The prep is pretty full now, A friend is wait-listed for Y5, this is going to leave very few places available at Y7 for 11+ entry.
They have already removed some troublesome children, which most parents see as a good sign because it is a new school, it isn't running at full strength yet, and I think people were worried that disruptive children wouldn't be excluded because they wanted the money!
When you look where it is, the children it will attract and the excellent teaching staff, and an already good disciplinary record, what can go wrong? It will always be less popular than the more established schools in the area because it is new, only time can remedy that.