I must admit being a fan of Elizabeth I. Not historically, but in terms of her character both in film and opera. One cannot Listen to "Gloriana" without going back to Donizetti's "Roberto Devereux", "Maria Estuarda" and "Ana Bolena".
But, on the other hand, there is a classic of cinema very much present: "The Private Lives of Elizabeth and Essex", with one of the best Elizabeths of all time: Bette Davis. And I am almost sure that Sarah Walker did study Davis' portrayal of the aging, imperious queen. That said, she is a total actress/singer, ably surrounded by a stellar cast and an visually sumptuous production.