As I said earlier it is very likely your Mom came to uK on MS Batory from Gdynia to Southampton.
I looked at the Board of Trade sites and as the question of immigration for 1946-1950 is over 30 years old, these records are at the National Archives at Kew. You can ring them directly at +44 (o) 20 8876 3444 between 9 am and 5 pm. ask if such immigration records are accessible.
Or you can write to The National Archives, Kew,
Richmond, Surrey, TW9 4DU
You can explain to them better than I can as you know all the details of your family.
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