"Sometimes the booking appointment system works for me, sometimes it doesn't"

I'm registered at the Lakes Medical Centre. Sometimes the booking appointment system at works for me, but sometimes it doesn't.

Basically the booking appointment system is done over the phone. You ring them and leave your contact details and wait for a GP to ring you back and ask you about your symptoms. If they think you don't need to be seen, they write a prescription for you that you pick up at the surgery and take to the pharmacy. If they think you need to be seen, they will give you an appointment.

I'm not sure about this system. My fear is that if something serious is wrong with you then it could be missed because they don't really check.