Hi clairesouthall,
I agree with sheila99. I would stick to the 28 day schedule, irrespective of bleeds, as you need the progesterone to protect your womb lining if using oestrogen.
I started off on a sequential regime like you timed around my normal period occuring after day 28. The first couple of months I bled a few days after I stopped the progesterone. I wasnt sure if this was a natural bleed or a withdrawal bleed from the progesterone. But I soon started having bleeds whilst i was taking the progesterone and not after which I think is my own cycle overriding the HRT. I have had bleeds either during progesterone or after since I have been on HRT.
Apparently 85% women have bleeds on a sequi regime whilst 15% don't. I have a notebook where I keep a record of when I take oestrogen only and then both oestrogen & progeterone and also when I bleed. Its useful to do this so you can tell your GP what's going on in terms of a bleeding pattern when you have a HRT review.
Good luck