So which is it? Was she right to shield her grandsons, or should she have left them and come to London?
Imho, the choice wasn't one or the other.
The Queen has lots of staff at her disposal. Some of those are presumably PR professionals trained in how to handle unexpected situations. She could have made a private statement from Balmoral or done something to publicly pay her respects to Diana whilst at the same time protecting W & H.
Instead she seemed to do everything she could to almost ignore Diana's death and apparently Charles had to beg to use a special royal flight to bring her body home from Paris. That did not leave an altogether good impression. Part of looking after W & H is surely respecting their mother's memory properly and acknowledging her untimely death, in public?
While I can understand that the entire family was shell shocked and protecting W & H was quite rightly their priority, harsh though it seems, the Queen can't just decide to act as a grandmother when it suits and ignore her wider role. Being a monarch doesn't work like that and the wider public, whether the rf like if or not, are party to the births, marriages and deaths of the rf family because that is the way the "faustian pact" works. If they lived their life privately, behind palace walls, the institution wouldn't survive would it?