I got a lot of help from World Jewish Relief Archives--and they even apologized for taking a mere two weeks to send me information on the entire family I inquired about, one of whom was a dear friend of mine who has passed away. I simply explained the reason why I wanted the information (not sure this is actually required). They did not ask for any documents from me at all.
Data included dates of arrival in Wales, addresses. naturalization dates, names of all family members, even the husband who traveled separately and birth dates.
This is a volunteer organization, so donations are helpful, but not required.