I recommend still going through the NHS as you'll likely need long-term treatment so don't completely reject it, still allow the referral to go through even if you do get some sort of private opinion. As your NHS GP will still manage the majority of it, prescriptions etc.
Adenomyosis where the lining of the womb grows into the muscle of the uterus, but localised to the uterus only. Thus, symptoms are mainly a before a period and during your period.
There are two types of adenomyosis: focal which is more like a few small/medium blobs across the uterine muscles in different places, so there is normal tissue but then blobs (more bigger so small-medium) across t
and in-between the normal tissue, in the uterine muscle wall. Then there's diffuse, which is a very small sort of dots and spots of the adenomyosis (uterine lining in the uterine muscular wall) but across the majority of the muscle wall.
Main symptoms:
• Irregular or heavy periods
• Pelvic pain
• Pelvic pain on passing urine (dysuria) and bladder symptoms sometimes
• Referred pain to the tops of the legs or back
Treatment can be a ranbe of (opioids - often only temporarily, NSAIDs) and contraception and hormonal treatments (gonadotrophin releasing hormones).
Also ask your GP to prescribe you NSAIDs (reduce pain and inflammation) such mefenamic acid and naproxen. You need to start taking NSAIDs 2-4 days before your period starts so that it can work at best capacity.
The link below has much more detailed and useful information.
https://www.nhs.uk/conditions/adenomyosis/