Addie, just to add to Northumbrian's answer: vocational qualifications are necessary for many jobs. I did a vocational qualification after my A-levels, because of the work I started doing. Vocational qualifications go up to degree-equivalent levels (and possibly even post-grad.) Some vocational diplomas (which are basically the first two years of university) can be converted into a degree by doing an extra year studying. Sixth form colleges tend to just be for A-Levels, and only for 16-18 year olds. Other colleges do both vocational courses, and GCSE and A-Levels, and tend to have a wider range of ages from 16 upwards.
The 'day release' is usually called a modern apprenticeship, and normally not for A-levels, but to complete vocational qualifications related to the job you are working in. So, a childcare apprenticeship would mean you worked in a nursery and went to college one or two days a week to complete a childcare qualification.
Because the number of people going to university has increased, it means that employers are looking for more and more work experience and other evidence that you would be as good employer, rather than just a degree. Many many people I know who went to university and good decent degrees spend a year or more doing temping work, before finding something more pernament, which often involved them doing some sort of post-grad vocational course, in something like management etc.
(Of course it depends what degree you do, vocational degrees like teaching, social work, nursing, medicine, etc, have an obvious route into work.)
A-Levels can be a bit like death. With the new A-Levels, student in England take exams at 16 (GCSEs) 17 (As-Levels) and 18 (A-Levels) Some puplis take exams in January and May, in order to spread them out, or they may be doing retakes of previous exams to improve their grade, because for the competition for university places. It's a lot of pressure, and pupils are also taking more and more A-Levels, whereas before people took three, maybe four, now more people take four, some are taking five. Other pupils are doing courses to complete an A-Level in one year, rather than two years, in order to give them more time in the second year to concentrate on other courses. Add to this that univeristies want more extra-curricular activities to help you stand out from the crowd, and I think some 16-18 years are massively stressed! Especially those who want to apply for Oxford/Cambridge, or for medicine, because demand is so high.
People keep saying A-Levels are getting easier, but I don't know if anyone has tested that! I know that when I was at school science A-Levels and GCSEs included a lot more topics and theories that would only have been covered at degree level before.