I've also just come off HRT after 9 years ( hysterectectomy 20years ago) and started hot flushes at night. A friend who is a retired Nutritionist recommends a natural Progesterone cream called Progestacare which you rub on daily, so by-passing the liver. I think it is starting to work but now the weather is so hot anyway it's hard to tell!!
If you want to know more I can give you details as it's not available in this country but has to come in from Alaska or some such!