No one outside of the decision makers at BT/Sky know the answer to that question. What I was told was that CS reps were to have been given a date for when the service was to start but that was withheld once it was realised the date wasn't going to be achievable.
A friend who is a Sky CS rep has told me a manager had told him it won't be any earlier than the last week of July and could be later. Again, I can't vouch for the validity of my friend's claim.
Slightly off topic but still on BT Sports.
It would appear that the BT Sports app for Smart TVs have catch up available. I have yet to test this as I don't often use BT Sports on my Samsung TV.
Direct quote -
The big-screen app also features a huge collection of on-demand content and highlights, so you can always catch up with your favourites events and shows if you are unable to watch them live.
Just more proof that BT Sports is far better than Now TV in terms of quality and content availability with 1080p at 50fps and catch-up.
Not to mention that 4K also coming sometime this year.
Yet literary nothing from Now TV when 1080p is launching and if any other improvements will be made based on previous surveys.
I don't think anyone really knows yet, and won't know until the announcement is made. Unless the admin of that linked site has received insider information he/she is guessing like the rest of us. BT haven't announced anything yet so any news would need to be taken with a large pinch of salt 😉