So, as George Street runs east to west north of the western end of Oxford Street and Charlotte Street north to south to the north of the eastern end of Oxford Street, clearly the new lizard will be called Mornington Crescent.
I wouldn't look north of the Inner Ring Road, it's way too common. The only other first names that appear to be left in Fitzrovia are Warren if it's a boy, which I'm sure everyone would agree sounds very regal indeed, or Anne or Margaret if it's a girl.
So, as George Street runs east to west north of the western end of Oxford Street and Charlotte Street north to south to the north of the eastern end of Oxford Street, clearly the new lizard will be called Mornington Crescent.