Normally NowTV is a monthly no contract subscription service.
You can buy NowTV 2 month entertainment gift card vouchers for £10 from places like Argos, Currys, Major Supermarkets etc or the NowTV stick bundled with either a 2 month or 3 month entertainment pass.
If you are a new customer, and go to nowtv.com/offers and follow the link offers then sometimes NowTV will have 6 month or possibly 12 month entertainment deals which won't be available for existing customers or a customer who has started a free trial.
Now & again, usually going on past experience during the Black Friday sales NowTV will offer existing customers a deal for a 12 month entertainment at a discounted rate with a full upfront payment.
Don't know if they will be doing a similar offer this Black Friday.
Not aware of any 12 month entertainment pass deals at the moment.
I usually buy either 2 x 3 month or 3 x 2 month worth of passes and get Now TV help chat to consolidate them into 1 x 6 month pass. Therefore, it may be possible to buy 12 months worth of Entertainment passes, e.g. 6 x 2 months, and get Now TV to consolidate them into 1 x 12 month pass for you.
However, before you start buying passes, it probably would be sensible to ask Now TV if this is something they could do for you.