The truth is that they missed the boat to obtain some early Neo delivery slots and the order size was not going to generate any discounts from Airbus.
Monarch have converted 15 options into firm orders today but surprisingly have specifed the Max8 rather than larger units. Surprising because this means that there will be nothing to replace the A321s
http://m.atwonline.com/airframes/mon...ing-737-max-8s