Of course he isn't insulting Longminster. If he were to do that, he would prove right then and there that her assumptions of him are correct.

And he cannot let her get away with such false opinions.

"Indeed, I have," he responds nonchalantly. "I have had the opportunity to catch up on my reading, for one. And I even feel slightly better in health."

(Okay, so the last bit may very well be a lie, but it sounds convincing enough.)