"sexual health clinic extremely busy"

I need an appointment with the sexual health clinic ASAP as I had a coil fitted a few weeks ago and I was told to return within a few weeks to make sure that it is still in the correct position. However they refuse to make appointments for this purpose, which is really inconvenient for me. They turned me away this morning from the GUM/sexual health clinic when I arrived at 9am as they had already reached capacity... Bearing in mind that they open at 8.30 it is a bit ridiculous to be turning people away so early. I was told that I would need to arrive at 8am to ensure that I would be seen. Apparently there is also a three week wait to book an appointment. I've had to wait for my day off to visit and get a bus there anyway so I'm not very impressed. I was loathe to take up my GPs time with such a minor issue and have been impressed with the staff/service (apart from waiting time) when I have visited the clinic before, but may have to see my GP about it instead now.