Sadly, no, I don't think Harding has gone.
Different sort of "head", I think.
From your Sky link:
Ms Appleton, who started work last week, has taken over from Simon Thompson, the former Apple executive who was appointed to run the programme in June, just before the first contact tracing app was ditched after it encountered technical problems.
Sky News understands that Mr Thompson took the role while he was on gardening leave from his previous job at online supermarket Ocado.