"This is one piece of research looking at one aspect" Yet clearly sets out that the arguments you and Deo have used here are incorrect. Far more reliable and relevant than your anecdotal evidence. Of course your not going to agree with it, cause as I said it makes your zeal about your own success a little harder to justify.
"What I have seen is that employers have been left totally confused by the different exams brought in. the GNVQ and BTEC qualifications are almost worthless for many because employers don't know what they are"
Empolyers are well aware of BTEC qualifications, they have been around in some form since the 1930s, and awarded as BTEC since the early 90s, you'd have to be a twit to be confused by them as they have been around in this form for over 25 years.
I took A levels, I also taught them, there is very little in the way of dumbing down. The language they are presented in became more accessible, and some syllabuses cut out content that was either obselete or not relevant.
Employers started asking for experience and internships instead of grades because it made a) their training cheaper and b) the more middle class graudates whose parents were able to help them started doing it to get ahead as others were now competing for the jobs as they had degrees (which used to be the barrier to entry) too!
The study proves this quite conclusively, also others in the past have shown that too!