Look at Jack Leach's county figures and look at Bashir's. Bashir is not even second or even third choice spinner for Somerset. I get the feeling Leach was something like the leading bowler in Div. 1, constantly near the top of the league too.
Same could be said of plenty of positions. Another obvious one would be Foakes. England first need to change their selection policy before anything else.
In my opinion, I'd change some of the squad now. Those who have failed, drop them. If you want to compete it's what you have to do. I'm not sure of selection rules but I'm pretty sure Ashes squads can be changed whenever you like. I could be wrong.