Hi, I have been researching the same. I have some valid information that i asked a qualified person to conduct and these are her thoughts :-
Jonas is the son of Lipman ‘Eliezer’ Lipman, although they don’t appear on the census. The marriage certificate is confusing because both the father of Julia and the father of Jonas are named as Lewis. However, it is not conceivable that they were brother and sister. Lipman’s Hebrew name was Eliezer and this often translates into English as Lewis. Also the Freedom papers quite clearly show Jonas’ father was Lipman.'
I am however sure that Jonas is the son of Lipman ‘Eliezer’ Lipman. We know that Lewis ‘Yehuda’ Lipman had a daughter Julia, and we know from census records that Lipman had a son Joseph. We know that Joseph and Julia married on the 6 June 1849 at the German Polish Synagogue and that the certificate listed both fathers as Lewis Lipman. We also know that Jonas Lipman married Rachel Jacobs on 4 July 1849 at the German Polish Synagogue. Again the father is recorded as Lewis. Since brother and sister would not be allowed to marry, we can assume that the synagogue scribe used the English translation of Lipman’s Hebrew name Eliezer (often translated as Lewis - several records of this in my husbands family).
The best evidence however, is the fact that both Jonas and Joseph received the Freedom of the City on the same day, 28 October 1856. The individual documents record: Jonas Lipman lived at 13 Ebenezer Square, his occupation was fruit dealer and his father was Lipman Lipman a Publican of Middlesex Street. Likewise Joseph Lipman is recorded living at 1 Ebenezer Square, occupation Traveller and his father Lipman Lipman a publican of Middlesex Street.
The London City Electoral Register of 1855 records Joseph at 1 Ebenezer Square, Jonas at 13 Ebenezer Square and Lewis at Still Alley.
In my opinion you are correct to assume that Jonas is Lipman’s son.