*Huge difference here (Midlands) I can only compare the schools that my children have attended to this is by no means guaranteed to be the same across the country. I have 1 in Grammar school and had several through high school.
The students are expected to go to University from the Grammar preferably a Russell Group Uni or Oxbridge instead of just being expected to get a few GCSE's and do anything upon leaving school as long as its not 'nothing..
School exchange trips appear to be to more unusual places so Iceland, Japan instead of the standard France or Germany.
I don't know any Grammar student who doesn't represent the school in some way. Either sport, music, STEM events, public speaking etc
Better access to national events at the Grammar. STEM/young engineers/Young Musician of the Year entries etc This does not happen at all at the local high school. There are no out of school activities other than football (boys team only) and netball (girls team only).*
All of this describes our local high school 😀
Trips to Vietnam, India, Iceland, USA. Extra curricular includes sailing etc, lots of stem activities, ditto engineering and English. High expectations, many go to Russell group, a few to oxbridge and the majority to university.