This would be a lovely item to have, especially since my daughter is currently talking of going as Lucy this Halloween. I shall be glad to join you in the search for this item and to fill you in should it appear anywhere!

I don't know whether good copies of these are still available.
You and your daughter could make your own. The cloak needs a piece of red material, gathered and with a nice clasp at the neck. I used a lightweight red curtain and sewed a large button on one side to match a loop in the curtain on the other.
Plastic daggers can be bought from costume shops. And your creativity can be focussed on the bottle of healing cordial. An old perfume bottle from a charity shop, with a cover you design and make yourselves?
Best wishes.

Thank you, yes making one ourselves did occur to me as well