Sir Gadabout by Martyn Beardsley

From chapters.ca:
Sir Gadabout is a walking disaster. Voted the "knight most likely to chop his own foot off in a fight," he shivers in his rusty armor when he has to face the brave Sir Lancelot in a joust. Sir Gads travels with his loyal squire Herbert to the wizard Merlin's cottage to get his ear put back in place after the joust, and survives an attack by Merlin's crazed guard turtle. Then, when Queen Guinevere is kidnapped, Sir Gads sets out to save the day Full of puns and sophisticated humor, the chaotic quest taken by loveable Sir Gadabout, loyal Herbert, and Merlin's sarcastic cat, Sidney Smith, will make every reader - child or adult - laugh out loud. Distinctive line drawings by Tony Ross, illustrator of the Horrid Henry series and the Little Princess series, add to the madcap feel of these adventures, while short accessible chapters make Sir Gads ideal for reluctant readers.