I hadn’t realised the Aventra Class of trains were effectively the ‘new’ Electrostar trains - just with a new name.
I feel it's a bit contrived - they don't look much like the electorstar series of trains. They're just EMUs that happen to be the successor to the Electrostar.
Most of the train is the Electrostar with improvements for compliance reasons and new technology. The Class 730 looks very similar to the 377/375 etc with the door connectors on the front and back.