It's bollox Gruntled - the "leading" boarding preps don't accept boarders below 8 / yr 4. That's all one needs to know.
Absolutely, though I suppose the SWs would argue that Arsula and husband wouldn't have gone for a leading school and may have discovered the 21st century equivalent of Dotheboys Hall which will take any kid whose parents are prepared to cough up.
Scratch that, who am I kidding, if a boarding school existed that would contemplate taking a 5 year old, we'd have heard of it. Badly done, SWs, badly done.