I have dug up the reference I half remembered. See A Welsh Born Icon: The history and origin of fish and chips. It is from the early days of the weblog and can't be reached from the Archives.
The great Claudia Roden credits Portuguese Marranos - Jews who had been forced to hide their ethnicity due to persecution - for introducing fried fish to this country when they arrived as refugees in the sixteenth century.
So we're both right. Hurray!