You are getting normal UK rate for being a normal UK based contractor. The author managed to hike up his rate by writing books, actively participating in confer

You are getting normal UK rate for being a normal UK based contractor. The author managed to hike up his rate by writing books, actively participating in conferences and etc. Anywhere he goes he can start conversations like: 'I'm the guy who's publishing books on the subject". All these things add some weight to what he does. Also,maybe, he's just better at selling himself than most.