I ended up having THREE course of azythromycin - one of 1x500g once a day for
3 days, one of 1g as a single dose, and one of 500g once a day for
five days. After each course I though the symptoms had subsided, but they came back within a few days. This, of course, could be coincidence, as symptoms do come and go (or it could even be the placebo effect - I was SO hoping the antibiotics would work!).
I have now arranged for another PCR assay to check whether ureaplasma is still present.