For int'l school student - when is the best time to study in UK ?

Ruby1219

My son is now in Yr 5 of GSIS. Many friends of mine with kids in international schools are considering when to send their kids abroad, e.g. USA and UK.
We plan to send him to UK, but not sure when's the best time.
Some friends said you have to send them in lower secondary, so that they can get in good secondary school and then good university, and also easier for him to adapt the new environment.
But my son is our only kid, we don't want to send him too early. And I was thinking since he's studying in international school already, it should be easier for him to adapt the new culture and environment !?
Can parents with similar experience and plans share your opinions ?

Thanks
Ruby

Ruby1219

Thank you thankful. Very good point.
That's one of my consideration too. I think family bonding is very important, and we now have a very intimate relationship with our boy. So it would be a shame to lose that even for academic result.
We don't really 'require' him to go to the top schools. More importantly we want him to have a happy life.

Ruby