I'll "Second" the recommendation for the BrewLab 4 day course. I also disagree about it being expensive; compare the cost to any other similar programs of similar lengths anywhere else (Germany, US, or Canada) and you'll find that it's many times cheaper than the alternative options. -I wouldn't sign up if I couldn't get into the final onsite brewing day, though.
I'll also confirm what some others have said about it being very much possible to pass the IBD Certificate exams just doing self-study.
I read through all the PDFs once months before the exam date, and then I got busy with work and was only able to spend 1 evening and one full day cramming for the exam and still passed with a "Credit" (71-80%).
The syllabus's knowledge measures really work well. If you could get the official study notes from someone who works at Diageo it would make it a million times easier, though. The Diageo employees hire a consultant to come in and teach them a test prep course and they go through previous year exam questions so they really get taught how they test works. When you sign up on your own you just get the study materials as a PDF and the Syllabus to use as a guide for what you should know.
Adam