No...no..no....It's Polly Maberly one of the most beautiful and talented actresses on the planet....beats me why she's doing an ad but I guess the money must have been good eh.
As Polly's ex-boyfriend, I'm happy to clear this up. The young Miss Maberly is in a Kenco ad, but not the one with the babysitter. Polly's ad (which she did for cash!) features her on the phone to a call centre while nurturing a cold coffee beverage. I haven't seen the Jessica Fox ad, but I believe that Kenco have abandoned the whole Cherie Lunghi thing for a string of young actress to represent the brand.
I don't think it's Jessica whatsername, I think she's actually called Jo. She went to Croham Hurst School in Croydon. Don't know for sure, or her surname, but she's an exact double otherwise.