I, too, mourn the lost brontosaurus - my son will never understand the appeal of ordering a brontosaurus burger,
I sympathise with the deprivation yoiur son will suffer - can I offer a reasonable substitute?

Bring him to Haworth, in West Yorkshire, (quite safe - foot & mouth is all around, but not in the town) the town where Charlotte Brontë and her sisters and brother grew up.
Go to the fish-and-chip shop there, and you will be able to buy him a "Brontë-burger."

(I wish that I was just winding you up, here )