Japhrimel is right - and there's no point taking piriton or applying calamine lotion, as the itching is being caused by the bile acids from inside your body and won't help the itching at all. However, the Urso has really helped with my itching, made a HUGE difference. Keep at your MW and GP - it's not their baby's life at stake - and after all, they are employed to give you the safest and least traumatic pregnancy and birth possible.
Because cholestasis is quite rare, unfortunately there is a lot of ignorance and misunderstanding about it and how to treat it, and the test results are slow to back up the symptoms.
Because of OC and the dithering and disagreement between the medical staff at the time, I had a failed induction and emergency c section at 37 weeks with my first child, and it was a truly frightening experience, a crap ending to what had been, until then, a straightforward and enjoyable pregnancy.
Although I have OC again in this pregnancy, this time I'm not frightened, I know what to expect, and the symptoms are being managed, as is the cause. However, it's only because I badgered the consultant (the MW said, "oh, you don't want to take any unnecessary blood tests", but I pushed for it) that we got onto it as quickly as we did. And even when the consultant confirmed that it looked like I did have it, and said that I would be GOING TO SEE the woman who specialises in this the following week, it's only because my pushy ex-MW mate rang the specialist woman that very day and directed her to view my hospital notes, that she rang me that same day to come in for Urso that very afternoon. Even so, had an insanely itchy few days before the drug kicked in, so thanks to pushy mate for moving things along for me. I've told specialist woman I am NOT happy with specialist chap for not setting up immediate appt with her, and she's advised me to complain to him direct when I see him at 38 weeks, and boyoboy! I'm certainly going to give him some grief.
Ahem. Sorry, rant over. Moral of story is, push for what YOU need, for both your and baby's health, as well as your peace of mind, no matter how they try to shut you down.