I'm not sure about exat times (yeah, I know it's what you asked for ) but the x-country is usually on BBC1 red button all day, from around 10am.
Horse & Country have a preview of the x-country course at 8.30 tonight and are showing Badminton Greatest Years all day, with slight breaks for Carl Heser and Mary King, if you fancy that. I'm currently watching Badminton 1994 and it's very interesting to see how horses, riders, equipment and courses have changed
ETA X-country is on from 12.30 and showjumping from 6 on BBC1 Monday.
XC coverage starts at 11am on red button. Not sure how much coverage I'll get on freeview though. Hopefully it will be 11-5 as advertised as planning a duvet day! Xx