Hi Peter. I haven’t had this issue but have you tried holding the button in on the tail gate for a few seconds until it beeps? There is a procedure to set the opening height. Can’t remember exactly what the process is. Would have to read the manual. This might reset it for you?2015 Discovery tail gate opens normally to fully open, then drops approx 1/4 to 1/3 closed. Is anyone having the same issue ?