Very good photos indeed! Thank you.
Both are reproduced in the IRS Sussex & surrey handbook, where they are credited to George Alliez, who was a prolific photographer of industrial locos, and always kept really good notes - I've got a couple of prints from him, and they are carefully annotated on the back. The top one is S6894/1927, and the bottom S6900/1927, both new to County Borough of Hastings, and both used at both powdermill and Darwell Hole. The Darwell hole job included creating an aqueduct to Brede, so we might be on topic!