Nope there is no indication on the actual television screen when you play a Sky Sports HD channel when on a Boost Pass.
The only place i can see the HD logo is on the dedicated Sky Sports EPG page by navigating to the Watch Live Sports on the front Home screen horizontal rail or whilst watching a Sports channel and pressing the OK button on my box remote to bring up the on screen information where there is a small HD icon added at the end of the Sky Sports channel.
I noticed if you access the main overall NowTV EPG either via the TV Guide or the TV Guide picture thumbnail box it doesn't show HD next to the live channel list ( which also includes the entertainment, cinema channels list).
Not sure the reason for this or if it's a limitation with the software or a bug which needs ironing out.
Tried everything written in posts but not working so now cancelled, waste of time for me untill they fix whatsevers wrong. But NOW TV dont seem too concerned because they are still offering the service in which for lots of people simply doesnt work.
You activate the Boost, having paid for it, by going into My Account on any device, finding the Boost Pass there, and selecting the button in there.
The HD then comes on automatically, but you may have to follow the instructions you will be given if you want to turn on 5.1 sound.
I see no other reports on here of the HD Boost not working, though there have been a few asking how to turn it on.
Was you on the older legacy NowTV Combo package that was introduced about 3 years ago with the NowTV Freeview Smart Box and TV passes on the same bill ?
I believe when NowTV introduced the Boost Pass back in November there was a problem where certain Combo customers didn't see the option to buy the Boost Pass on their account.
Don't know if it's resolved now (perhaps a Combo customer can confirm either way).
I am guessing the 3 month offer is not a Mobile Sports Pass where the Boost pass doesn't work.
With a Mobile Sports Pass you are only entitled to five Sky Sports Channels (see above link).
If you have a full blown Sports Pass (not Mobile).
Then on your main playback device such has a NowTV Box / Stick, Games Console, LG or Samsung Smart TV, sign out of the NowTV App and sign back in again to trigger the Boost Pass.