Thomas: ... and as a result, the price of minibus hire in the locality has increased dramatically over the last year.
Jean-Luc: That's interesting. Thomas, thank you, but I think it's probably best left for another meeting.
Is it gramatically correct to use "left" here? Can I say "best to leave"?
Yes it's fine. You could also say "I think it's probably best to leave that for another meeting".
"Invading armies have no rights." Noam Chomsky