This is what I’m going to call basic, probably-be-useful-to-know context. Am I writing a historical epic in the British iron age? No. Am I taking some cues from what we know about the British iron age and going from there? Absolutely.
The iron age supplanted the bronze age when people figured out how to work iron, because iron is stronger and generally more useful than bronze. This isn’t to say that they stopped working with bronze or its alloys, but there is a definite technological shift in the various archaeological sites.