I have Sky+HD, and used to Sky Talk & Broadband, but now have BT Phone & Broadband.
I believe that you had to apply before a deadline for BT Sport HD (1&2) but you can still get these either by applying online with your Sky details or over the phone with BT. You shouldn't need to have your Sky box connected to a phone line, but may need to initially to get it rolling (if so, then you can disconnect thereafter). If you speak to BT (nicely) you may be able to sweet talk them into giving you the HD channels

But guys remember that you need to cancel the free BT Sport HD package in a year's time, else you will be charged approx. £10/month. However, once cancelled and you're still with BT Broadband, you will still get BT Sport 1&2 but non-HD. Set reminders

Red