PCOS and septate uterus

Dear Professor Winston,
I am 33 years old, and my husband and I have been trying to conceive for four years now. I was diagnosed with PCOS at 16 and prescribed Dianette to control the symptoms and to give me a regular cycle. I stayed on Dianette until age 26 when I instead switched to Glucophage for two years and then Glucophage and Aldactone for a year, under the supervision of an endocrinologist and again in an effort to control the symptoms of PCOS (absent periods, weight gain and hirsutism). None of the drugs were successful and I have never had a natural menstrual cycle. I came off all medication four years ago when we began trying to conceive naturally. I am otherwise very fit and healthy with a BMI of 24.7. My husband is equally fit and healthy and was told, comically, after his semen analysis results came back that he has “super sperm”. In February of this year I took Provera to induce a bleed and then began two monitored cycles with Clomid. I ovulated on both cycles but my endometrial layer was too thin and the clinic advised against continuing with the treatment. A HSG test showed that my fallopian tubes are not blocked but it also showed that I have a bicornuate or septated uterus. The clinic attempted a hysteroscopy but were unable to complete it (I was not given any anaesthetic). I underwent an MRI instead which did not give a conclusive answer as to the cause of the malformation but it was enough for the clinic to advise proceeding with another treatment, as the malformation looks to be very mild. I am now mid-way through a monitored cycle with Letrozole, and though my ovary has responded well and produced a large follicle, my endometrial layer is again too thin (3.4 on day 12, with the follicle measuring at 17). The clinic has advised me to see this cycle through but to then discontinue with the Letrozole and review my case. Ovarian drilling was presented to me as an option before I began the Letrozole treatment, as I appear to be unlucky and suffer many side effects on hormonal medications (hot flushes, night sweats, blister eczema and headaches on Clomid hot flushes, night sweats, nausea and headaches on Letrozole). I opted for the Letrozole treatment instead, as I understand that the ovaries can take up to six months to recover from the drilling, and that Letrozole is not associated with thinning the endometrial layer in the way that Clomid can for some patients. Can you advise me on what further investigations and treatments I should request from the clinic at this point? Thus far the only treatment for the thin endometrial layer that has been suggested to me by the nurses monitoring my cycles is acupuncture, which I tried before in a vain effort to establish a menstrual cycle and I am not at all keen to try again. Regardless of any advice or insight you might be able to give me on my own case, I would like to offer my sincere thanks to you for your participation in this project. It gives me heart to read such informed, honest and kind advice to women in similar circumstances to mine. Many thanks, C