In legal reality, that's the job of the executive. The trustees are there to make sure that the executive do their job properly. In the words of the gov.uk website:
That word "ensure" doesn't mean "do". It means "make sure someone does".
https://www.gov.uk/guidance/charity-trustee-whats-involved
I would say yes and no. Normal business yes but if the ship is heading the wrong way, the trustees need to use the instruments in the constitution or charter and failing which to other means to set things right. It appears from Op's mails that he can no longer ensure that the executive is doing this right.