Look out for a letter or email about Bt Sport HD renewal. I had the free service, that I never used, up to 1st August. You have to phone an 0800 to cancel.
From letter:
Keep getting BT sport for free
Avoid paying £6.75 mth you need to renew your contract. Phone 08004320025 to keep getting our three channels for free.
Further down:
When you signed up to BT Sport we gave you free HD until 1st Aug. After that, we'll move you to our standard HD price of £3 mth.
What the hell is standard HD?
I just phoned and cancelled the BT Sport.