I think Chris' point is that it's very broadly drafted; the magic word is "premises". "Premises where a person has his home" is listed as one of the categories that may be excepted. Premises definitely includes tents (12.1). "Vehicles" seems to include private vehicles, which makes sense as most public transport and taxis has been smokefree for a while. Additionally section 4:

"The appropriate national authority may make regulations designating as smoke-free any place or description of place that is not smoke-free under section 2."

I've not yet worked out who this means by "authority". It's part of the general trend of arrogating large chunks of potential power from Parliament and moving them to Statutory Instrument or executive Order.

Personally, I prefer it, and think the time is now right for it, but it's clearly the last step before a total ban on smoking everywhere. I'd give it 10-15 years before tobacco is a class C drug.