Miriam was actually Morris's niece, being the eldest daughter of Morris' brother, Henry Fileman (b. c1842).
Henry Fileman had indeed married Theresa, the daughter of Lewis Lipman/Liebman Leopold), in 1869 in the Masonic Lodge, Bedford Row, London. The marriage was even announced in the Jewish Chronicle, and there is a corresponding civil registration.
In order to be married by an authorised rabbi and thereby obtain a civil marriage certificate, a Jewish couple needed to obtain a marriage authorisation from the Chief Rabbi in London. The authorisation was granted after the authorities were satisfied that both parties were halachically Jewish or that they had an acceptable Certificate of Conversion. Throughout much of the 19th century, the only acceptable proof was the ketubah (Jewish marriage contract) of the bride's and groom's parents.
Morris' parents (John s/o Benjamin and Mary d/o Jacob Levy) had married in the New Synagogue on 21 Mar 1841; his grandparents in the same synagogue in 1814. There would, presumably, have been no difficulty in proving his Jewishness.
Theresa's parents (Lewis s/o Isaac and Marian d/o Andrew Harvey) had married in St. Helier on 2 Sep 1846; their marriage being, apparently, the first recorded in the Jewish marriage register. Lewis (b. c1816 in Fürth, Germany) was apparently president of the congregation for a while before his death in 1877. The congregation acknowledged the authority of the Chief Rabbi and the Rabbinical Court in London. Again, one would have thought that Theresa's Jewishness would have been indisputable.
There is an online database of marriage authorisations issued between 1880 and 1922. It does not include a record for a Fileman-Fileman marriage. It would, therefore, appear that either Morris or Miriam were unable to produce the necessary proof.
This does not mean that Morris and Miriam did not marry, merely that they possibly underwent a clandestine marriage (stille khuppah = silent canopy/marriage ceremony) officiated by a religiously qualified, but unauthorised rabbi. They would have been married in the eyes of God, but not in the eyes of the law, and there would be no official record of the marriage.
Justin