app layout view frozen

Got the Watch 7 this morning. Went through setup, tried a couple of faces, tried some of the apps. Just now went to the app layout view screen (icons or list view) by mistake, but now I can't get out of it. "Cancel" won't work. Pressing the big button any number of times does not return to the watch face. If I leave it alone, the time eventually appears as a pure digital readout, but the moment I touch the screen or the big button, I am back at the app layout screen. Tried resetting the home screen layout from the iPhone Watch app but no response. Don't want to erase all content and settings and start again but looks like I may have to--with no guarantee this won't happen again!

Anybody any ideas?