Can I claim after taking a replacement flight?

Possibly. Accepting rerouting does not by itself answer every compensation question. Keep the substitute flight's arrival time, the cancellation notice and the airline's reason; a full refund for transportation you used is a different issue.

What to check

Start with the airline’s notice, the original schedule, and when you actually reached your final destination. A departure delay and an arrival delay can lead to different answers.

What to do next

Ask the operating airline for its written reason. The rule checker can point you to the conditions worth reviewing.

Official sources

• European Union / Your Europe: Air passenger rights
• UK Civil Aviation Authority: Cancellations