Translate the following English sentence to French:
"I want to congratulate him, sadly in his absence, for the thorough and rigorous way in which he has undertaken the preparation of his report - and also for putting up with my being such a thorn in his side!"
Je voudrais le féliciter, en son absence malheureusement, pour la manière exhaustive et minutieuse dont il a entrepris la préparation de son rapport - ainsi que pour m'avoir supporté, en tant que source d'irritation constante !