OK.. this confuses the hell out of me: as far as I can se they are both 512Kb unlimited serivices with all the same bell s and whistles in terms of domain hosting, webspace and the rest - is there something I'm missing?
First, neither state they are unlimited products, it is important to realise plusnet don't sell their products as being unlimited. There are no caps imposed but that does not mean they are unlimited and plusnet may impose the fair usage rule within the T&C at their discretion.
Homeworker (and the faster homeworker pro) is designed for users who work from home but need to be connected to their company network a lot (usually via VPN). Normally these accounts are paid for by your company.
Broadband home premier is designed for residential use where you won't be connecting to your company network via VPN (or other software). Accessing things like company email or occational VPN acess is fine but if you spend most of your day connected to your company network you must use a homeworker or homeworker pro package. Note: this account still allows VPN access, just not for business use - i.e. so you can access your home PCs remotely or access someone elses PC.
Note: the homeworker product range is due to be revamped on thursday.