Natasha is definately above Charlene in the pecking order and arguably Nina too when it comes to covering the evening bulletins. She seems to fit in at ITV News too - never really liked her on the BBC or C5 (though Strictly really harmed her credibility as a journalist, something we're seeing now with Susanna Reid) but she seems to fit in with ITV News - especially Alastair Stewart. Did they present London Tonight together in the past?
Well I suppose with Charlene been an ITN contractor and Natasha been freelance I think we could see more of Charlene on the bulletins, Charlene has covered News at Ten a bit recently too. I do think she is good presenter too.
I do think Alastair & Natasha did host London Tonight together in the past, almost sure.
Natasha Kaplinski? she covered for Nina Hossain whilst she was on maternity leave, but they've not presented London Tonight together AFAIK. It's been single headed for quite a few years now.
According to wiki (I know, sorry, my only source!)
"In 1999 she moved to ITV's London News Network where she hosted London Today and London Tonight and a political programme called Seven Days." Don't know what capacity she presented.