BT Group C# Software Engineering Professional interview questions

Approached via Hackajob. Given a C# project technical task to do, requiring multiple specifications. Progressed to 1 hour time strict interview that then elaborated on previously submitted project, and was given 30 minutes to review / explain what has been done, and then 30 minutes to implement new specifications whilst being spectated. Company was hands off and distant. Not much enquiring; just instructing. Was informed that there were further culture / HR interview processes after, but was rejected after interview. Absolutely zero feedback given.