Hi Vince,
There is a youtube channel (Dharmayai Obai) with sermons from 2 monks, who follow the same teachings of Waharaka Thero. Sermons of one of the monks is in English.
You can search for the sermons on youtube “Dharmayai Obai BBE”. Below is a link to one such sermon. BBE stands for Budhu Bana English.