Enclosed public places - and work places.
You will be able to smoke at bus stops, not in bus shelters.
In pub gardens, not inside the pubs.
A public place is anywhere that the public can go. You will not be able to smoke in the workplace - unless you work totally alone in your own building (at home perhaps).
Interestingly, if you are expecting a visit from anyone in their working capacity - a doctor, builder as examples - you will not be able to smoke in your own home whilst they are there.
http://www.smokefreeengland.co.uk/