It is certainly highly probable that Esther was Jewish, but she would not have married in a synagogue unless her husband was Jewish too. Besides, the marriage would still have been registered, and there is nothing in the index in England or Wales. Unless Christopher was Jewish (and it is highly unlikely, Christopher not being an especially popular Jewish name!), then it is likely that both families would have objected to the match. They may have married in another country - ScotlandsPeople is not showing anything likely north of the border, but France is possible, I suppose. Alternatively, they may have just opted to cohabit - this was much more common than one might suppose.