Although The Daleks is an iconic story in the history of Doctor Who it has, surprisingly not resulted in many direct sequels.
The TV stories which follow more or less retcon the situation in The Daleks. From The Dalek Invasion of Earth onwards, the Daleks are planet-conquering despots zipping around the universe with access to time travel technology and feared across the cosmos. Quite the contrast to their city-confined desperate survivors of their first appearance.
But a number of expanded universe stories have returned to Skaro to examine this earliest iteration of the malevolent pepperpots.
Is there a story or explanation that tells us how the Daleks managed to improve their technology so much (in The Daleks they can’t even move outside the city), and also develop time travel, or is it just “because Daleks needed to be a bigger threat”?
There’s Terry Nation’s ‘this must be from an earlier point in their history’ guff in The Dalek Invasion of Earth which really makes no sense other than ‘I’ve realised these guys can make me rich, but that won’t happen if I leave them stuck in the city on Skaro’…
I agree with @fingersmash here: Return to Skaro is fine, nothing special, but The Last of the Romanovs is a great historical. It’s educational, genuinely touching and very interesting.