Hi,
Found this on another site. Ugly but works...
Just Found this solution on the cult of mac website:
You can still trash all emails at once... it's just more convoluted.
Go to your inbox, Tap Edit, then Mark All, and then Mark All as Read. This will then close the Edit mode.
Tap Edit again, and tap the top message in the inbox. Press and hold the Move button with your thumb.
While holding the Move button, uncheck the top message, and then release the Move button.
You will then be on a screen with a trash icon, click it and your emails are deleted.
Not quite as simples as the old way but it solves the problem.
Marc