The reading was 74kph at about 3m50s (40kts).
Wristwatch GPS speed runs in WA suggest 70kph is achievable on yer average kite without requiring special gear such as board shorts and a screw top fly, albeit its probably faster than most ppl would want to go.
The kite speed record is ~50kts, but this is an average over a measured distance. Its interesting that it's ONLY 50Kts - meaning yer average kiter is probably able to attain 75% of max possible kite speed without even giving it a thought.