Documentarily qualified: FRI 26 AUG (email received at 03:46 BST)
Interview letter: FRI 30 SEP (email received at 07:36 BST)
Medical date scheduled: MON 24 OCT
Interview date scheduled: TUE 01 NOV
Having the same problem registering with the Visa Appointment Service as mentioned above. Will try again in 5 days.