Whens it on?
Depends on where you live. There are repeats running at the moment in Australia and the UK, and probably elsewhere.
What Channel is it on?
Again, depends on where you live. ABC & UKTV in Australia, PBS in the US, ITV in the UK, KRO in the Netherlands etc.
Whats it about?
It's a detective series set in World War II, in Hastings. AH weaves the background of life on the homefront with mystery and murder.