"out patients reception"

I recived an appointment for 4.45 last Friday to attend a clinic .on arrival at out patients we found everyone had gone home and the appointment letter did not give details of which clinic I had to attend. I know everybody wants to get home of a weekend so if clinics are going to be late wouldn't it be advisable if the letters that come out have the clinic number on them, instead I had to hunt around till I found the correct place