Easy way to clear messages in bulk?

Hi there

I'm using an a Banglejs2, with my iPhone, and it's handy to see notifications but it's not obvious to me how to clear them from my watch without going individually into each message and swiping left on the messae to delete it.

Is there another way to do this in bulk that's easily accessible?

I can see in the messages app there is something like this:

menu = Object.assign(menu, {
    /*LANG*/"Mark Unread" : () => {
      msg.new = true;
      checkMessages({clockIfNoMsg:0,clockIfAllRead:0,showMsgIfUnread:0,openMusic:0});
    },
    /*LANG*/"Mark all read" : () => {
      MESSAGES.forEach(msg => msg.new = false);
      checkMessages({clockIfNoMsg:0,clockIfAllRead:0,showMsgIfUnread:0,openMusic:0});
    },
    /*LANG*/"Delete all messages" : () => {
      E.showPrompt(/*LANG*/"Are you sure?", {title:/*LANG*/"Delete All Messages"}).then(isYes => {
        if (isYes) {
          MESSAGES = [];
        }
        checkMessages({clockIfNoMsg:0,clockIfAllRead:0,showMsgIfUnread:0,openMusic:0});
      });
    },
  });
  E.showMenu(menu);

It's linked in github
I can see this code linked

https://github.com/espruino/BangleApps/blob/master/apps/messagegui/app.js#L263-L304

but I can't see how I would call up this menu in the Watch UI.

Suggestions very welcome.