Hi, some women on this forum take 200mg vaginal utrogestan for 12 nights every six to eight weeks. This is with medical supervision, of course, but it reduces the frequency of the utrogestan phase. If you search for 'longer cycle' you will find reference to it. Not sure if this would work in perimenopause because the natural cycle might break through, but you could ask your doctor.
Utrogestan intolerance due to being small - maybe? Who knows?!
I can't comment on the Prof Studd regime of 7 days. For me, that seems too short. My own doctor has said that the 'transformation dose', ie the amount needed to thin the endometrium, is 2000mg utrogestan per cycle as a minimum. So, 12 days x 200mg gives 2400mg or 28 days x 100mg gives 2800mg.
However, we are all different and if you can be monitored very closely and have scans then you can afford to try less utrogestan.
You have said you are only using 25mcg patches so that is a low dose. Taking utrogestan vaginally every other night continuously may work for you. Again, another option to discuss with your doctor.
Perimenopause is just such a difficult/random time. Whatever you decide, in my experience it is important to keep it as simple and consistent as possible, sticking with one approach for at least 12 weeks to assess it. I hope you soon find something you can work with. X