I hope that's the one, as you stand a chance in 1851. There's another in St Pancras in June 1847 - and on the IGI at St Pancras there were births of Ann in 1838 and Mary 1840 where the parents were John and Charlotte, so this one might be worth a second look as well, as well as checking 1841.
Have you found Emma Aslett in 1851? I've found her in 1861 if you need details (birthplace transcribed as Sangford which didn't help!) in St Saviour
Regards
David