Abraham Moscou and his wife, Schoontje Veerjong, did not move to London from Amsterdam.
Schoontje Veerjong was my great great grandmother and it was her son, Isaac with his wife Elsje Ditenheim and their daughter Schoontje who moved to London from Amsterdam. They changed their names several times, according to different English censuses and eventually became Isaac and Matilda Fairman. Their daughter Schoontje was my late Great Aunt Jane, called by the family Janey. I met her when I was a child and have it on good authority that she spoke Dutch as a child. All of Isaac and Matilda's other children were born in London.
It also appears that a lot of researchers have Abraham Joseph Moscou having died in 1856. This does not make sense as he is listed as being at his step-son’s marriage in 1863! If you go into:
https://www.wiewaswie.nl/en/search/search-results/record-details/a2...
you will see that it gives details of Isaac and Elsje’s wedding and one of the witnesses listed on the attached wedding certificate is Abraham Joseph (A.J.) Moscou. His age is listed as 58, which would have been correct, being born in 1804. His occupation is listed as cook. These details were also confirmed to me by a compiler from Ashkenazi Amsterdam, who was able to translate the Dutch wedding certificate for me into English..