No Graduation in the UK?

[Steve]

In the 'Trams and Tolleys' sub-thread, Brian gave a link to his
website where he explains differences between US and UK language.

On the subject of Education, he points out that students do not
graduate. They simply take their GCSEs (OWLs or O-Levels) at 
roughly age 16 and that is it. 

In the USA, as you know, they try to get all students to pass
the public education standards to assume at least a minimum
level of education when the student enters the world. Though, I
must point out, that legally beyond a certain age, a student can
not be compelled to go to school. In many places that age is 16.
Keep in mind that US students are usually 17 when they graduate.

So, my question is, what are the options for students who don't
do well on their GCSEs, yet still want to do well in life? Are
they allowed to take them over? Are they forced to go back to 
School as they are in the USA? Can they continue on in public
(government sponsored) school, or if they need tutors and so 
forth, do they have to pay themselves? 

Within limits, in the USA, you are forced to keep going to 
school until you get it right; until you make the minimum grade.

In the UK, what are the options?

Thanks.

Steve/bboyminn