Just another update even though I started this topic in September.
The bleeding became progressively lighter, to light spotting after several weeks and then to minimal spotting with a one-off day here and there with no visible signs of spotting. So, just when I thought that the bleeding had stopped... the spotting started up again. Only light spotting for a few days, and then followed by about 10 days of nothing at all at around the three months point.
So that was great, the Mirena was doing it's job as expected. And then today and yesterday - spotting again.

Perhaps, as you say Dancing Girl, a wee bit of spotting now and then is within the normal expectations of using the Mirena. I've been keeping a record on the printed calendar on the back of the Mirena information booklet and I'm seeing the consultant at KCH next month. I have a few more weeks to observe and record any bleeding and spotting which I will then take to my appointment.
So, at about the three months the bleeding/spotting stopped but after 10-12 days a wee bit of spotting has appeared. I was getting breakthrough bleeding oncontinuous Utrogestan and was having a light bleed every 12-14 days for about 5 days. I have the option of 200mg Utrogestan daily but after going through all of this rigmarole of the Mirena, I'm more inclined to stick with it.
BTW, I had no improvement in sleep with the Mirena, nor did I have better sleep on Utrogestan. I have ME/CFS and my sleep pattern was disturbed anyway. My consultant says it only really helps sleep problems if they are caused by the hormone changes associated with the menopause so he warned me it probably wouldn't help in my case, and he was right.
I was a bit annoyed with the info on Dr Studd's website saying that HRT can help with CFS/ME. That's misleading. It can only address the problems associated with the menopause. If otherwise healthy women experience tiredness at the menopause that probably can be helped by HRT but there's a world of difference between that and someone with ME/CFS. HRT hasn't helped my ME symptoms one jot, but it's probably one of those situations where "your mileage may vary". I'm saying this for the benefit of other women with ME/CFS, not as a criticism of anyone here who genuinely wants to help people. I'm taking HRT because of osteoporosis not because of classic menopause symptoms so for me it's all about what the DEXA scan looks like rather than how I feel symptom-wise.