Where was The Iron Duke filmed?
1934 film by Victor Saville
The Iron Duke (1934) was filmed in Welwyn Garden City and Shepherd's Bush, 2 places named in its Wikipedia article's Shooting section, in the United Kingdom. Wikidata records no filming location for it at all, so the article is the only recorded source. Each place says where its claim comes from.
Places per Wikipedia's Shooting section
Wikipedia’s Shooting section names 2 places. Each links to the sentence that says so.

