How to create custom service and characteristics

As another test, using this code on the puck

function SetupServices() {
  NRF.setServices({
    0xBCDE: {
      0xABCD : {
        value : "Hello", // optional
        maxLen : 25, // optional (otherwise is length of initial value)
        broadcast : true, // optional, default is false
        readable : true,   // optional, default is false
        writable : true,   // optional, default is false
        notify : true,   // optional, default is false
        indicate : true,   // optional, default is false
        description: "My Characteristic",  // optional, default is null
        onWrite : function(evt) { // optional
          console.log("Got ", evt.data);
        }
      }
      // more characteristics allowed
    }
    // more services allowed
  });
}

SetupServices();

var cnt = 0;
setWatch(function() {
  if(cnt++ % 2 === 0)
    LED1.set();
  else
    LED1.reset();
  NRF.updateServices({
    0xBCDE : {
      0xABCD : {
        value : [cnt],
        notify: true
      }
    }
  });
}, BTN, { repeat:true, edge:"rising", debounce: 50 });

Connecting via nRF Connect iPad app, I can see the service and Characteristic ABCD..
It's default value however shows as 0x0D and pressing the puck button (which does toggle the led) is not updating that value