Ruth,

1939 British card for Willy SELIG, which exempts him from internment.  Lists his date and exact place of birth, and current address in Kenton, Middlesex.  He is a medical doctor.
https://webarchive.nationalarchives.gov.uk/20131101074629/http://www.movinghere.org.uk/deliveryfiles/PRO/HO396_84_246/0/1.pdf

If he naturalized in Britain, perhaps his nat papers would reveal his date of arrival?

Regards,

Sherri Bobish