I've had two DDs go through Prendergast. DD1 stayed for sixth form but her sister will go elsewhere because the subjects she currently wants to do aren't on offer.
DD1's experience of the sixth form at Prendergast was fine overall but it was somewhat lacking in enrichment opportunities e.g. seminars or talks, visits to universities etc. especially in comparison to other local sixth forms. The EPQ felt very disorganised (I'm not sure if any of those who started it actually completed it) and it very much felt as though the expectation was for everyone to want to go to university meaning there was little information available about degree apprenticeships or other pathways.
The sixth form is very separate from the main school which I find quite
odd as the sixth formers at the
school I went to were involved in lots of aspects of school life e.g.
technical jobs for productions,
running clubs, supporting younger
students, playing in music groups,
running sports day and charity
events.
That said, the subject teachers are brilliant. They know their stuff, are passionate about their subjects and care about their students. Although she's left, DD1 still receives occasional messages (via her sister) from a couple of the teachers about opportunities they think she may be interested in.
I don't think I know anyone who has gone to Charter North so I can't offer any insight on that one. DD1 liked that Prendergast has a very casual dress code and that the split site means it felt as though they weren't on site all day. It's what she was used to though and I think she may have felt stifled by a single-site sixth form in a way I think her sister won't.