is because they cannot get an appointment time which is remotely suitable for someone who goes to work.
If I want to see a doctor then I can either make an appointment for the middle of April (earliest time when bookings can be made) or take pot luck on the day. The pot luck which is available today is 3.30pm, no alternatives available. This would be great someone wanted to take a DC to the doctor outside of school hours. Sadly it is totally useless to me as I would have to leave work at 2.45. My employer is strict, I cant take an afternoon off to go to the doctor.
So would it be so very difficult for the surgery to work out that only offering appointments on the day at fixed times or in over a fortnight's time is not serving a large proportion of the patients well?