All I was told to bear in mind was that if I did the apprenticehsip, after a few years the people of the same age would be leaving uni with good qualificaitons and up to date research knowledge etc, so if going through the apprenticeship, you'd have to be going under constant training to keep up.... but then it depends on how common internal promotion is at BMW(?)
If it was me I would at least go through A-levels, but again I don't know what promotion prospects are, or how easy it is to get up the ladder from the bottom.