I agree with the others to put her on the waiting list. At least then you have the option of going when an appointment comes up.

Also I have just had my 2 yr check up with the MHCN and the next scheduled one is for 3y 6m so I would also ring the MHCN and book her in for the 3y 6m check which is standard.

You need to do what you think is right and what you feel comfortable with. Your family can offer advice but ultimately you need to do what you feel is right for your daughter. If you truly feel she may have problems then for your own peace of mind get her assessed.