HI cqcq, I too was on northisterone, both my cycles were with rfc (nhs and private)like you was incase would overstimulate (which I never have) first time I was on notheristone for 1 week, second time was for 4 weeks! When I questioned it the second time they told me they had to keep me on it longer because they didn’t have an available egg collection date and the nurse said the table kind of “paused” me so to wait for ec date, I wasnt oveely happy at this as I felt I was going tim their schedule instead of them going to mine, however subsequently the first round didn’t would and second did (sadly ending in miscarriage) although I’m not going back to rfc for my third cycle, I still would use them again in future, they were v good. Best of luck for your cycle!!