Hi redandpinkstripes
Sorry to hear about yout pain.
I would definitely change from the tibolone - as per the others, the oestrogenic component seems to be stimulating the endometriosis and causing the pain and it sounds like you need more progestogen. One of the known potential side effects of tibolone is endometrial thickening and bleeding and even though it is suggested as a suitable HRT for endometriosis, it sounds like it's not appropriate for your situation because it's not working - as evidenced by the pain.
Here is what it says on this website:
"
Endometriosis
There is a small risk of reactivation of endometriosis with HRT use and any recurrence of symptoms should be reported. If a hysterectomy has been performed for endometriosis, the choice of HRT use thereafter should be influenced by the extent of endometriosis at the time of the operation. Since hysterectomy often causes a premature menopause, it is often advised to take HRT until the average age of the menopause; 51 years. HRT after hysterectomy usually consists of estrogen only. However, in the presence of endometriosis, estrogen may cause stimulation of residual deposits and consideration should be given to using continuous combined (estrogen plus daily progestogen) therapy, or tibolone, though little research has been done on the effect of different types and duration of therapy. Medical treatment of endometriosis often involves ovarian suppression which, along with ovarian removal, may increase the risk of osteoporosis. "
https://www.menopausematters.co.uk/atoz.php#GlossENot sure what you mean here: "I've been referred to a specialist bsge one now.". Bsge?
In any case - referral to an endometriosis specialist would be a good thing so see how things go after the appointment.
Re taking a stronger progestogen along with additional oestrogen as part of HRT. From memory Provera - Medroxyprogesterone has the highest affinity for progesterone receptors, better even than norethisterone (can't find where I read this as it was years ago!), so that would be a possibility. You could choose an oestrogen preparation at the type and dose which suits you - patch, pill or gel.
Hope this helps and do keep us informed

Hurdity x