Google ITU-R BT.2020-2 10/2015 for the specifications
Typically the UHD transmissions are 2160p25 4:2:0 10 bit colour AVC/H.264
Audio is DD 5.1
According to sources the BT Sport UHD bitrate is around 30 mbps
The reality is that other than computer generated sources and experimental files there is not going to be any 50fps material for a long time.
In comparison Netflix requires 25 mbps however the bitrate is variable with average of 16 mbps. Due to the HEVC codec much more efficient than H.264 the quality is same if not better than UHD broadcasts based on H264
Netflix is also one of the few sources that has UHD premium or Dolby vision