A NOW TV box and a NOW TV subscription are two different things. Unless there is a change of law Sky (and any seller of TV equipment) don't have to inform TV Licensing.
The Wireless Telegraphy Act of 1967 (as amended) has been repealed meaning that from 25 June 2013 onwards, TV dealers are no longer required to notify TV Licensing when they sell or rent out TV equipment.
Source: TV Licensing and the law
@xinam I thought at first that your question was as a result of the proposed law change that will require a TV licence to watch BBC iPlayer.
I do have a licence ( free over 75) but have been wondering how the rules will be applied.
First, my post will be based purely on my own experience rather than any objective information.
OK, organisations, companies, etc. tend to keep their dealings with official and quasi-official bodies very secret, i.e. information asked for and supplied. Unfortunately, until the passing of the "Freedom of Information Act" this has always been seen as normal, i.e. colloquially considered to be "the norm".
And even now this "don't tell" attitude is still very much prevalent throughout the UK, so unless you make an official FOI request you are unlikely to receive an answer.
I think it's in the interests of sky customers to know if there is data sharing going on with this third party (BBC TV Licensing).
The term 'data' can mean anything. I very much doubt that NOW TV are passing customer names and addresses to TV Licensing. There's no requirement for them to do-so as NOW TV is an internet based service!