TuckDB has 2 sets of Darlington cards with Places set to England - Lancashire.
The correct value for Places for Darlington cards is England - Durham.
The sets are:
Set Title DARLINGTON Card Number 5921
https://tuckdbpostcards.org/sets/12444
Set Title DARLINGTON Card Number 5594
https://tuckdbpostcards.org/sets/16735
I will add a link to each of the 17 individual cards if it will make it quicker for you to update Places.
All other Darlington cards have the correct Places of England - Durham.