Hi Leony
I don't think anyone responded to your own issues listed in this thread. That sometimes happens when focus is on the person who started the subject.
I, too, had a car accident. It was in 1985. I had three broken ribs and broken T12 vertebrae. I attended a Chartered Physiotherapist about 2 years ago. He is a specialist in myofascial release and 'shorter leg syndrome' caused by out of alignment pelvis; easily caused by accidents when we are children, the muscles adjust and slowly our skeletal alignment adjusts to the new out of alignment position. He told me that he knows of some women who have had hysterectomies trying to eliminate discomfort and pain - when it is the skeletal alignment.
This particular physio travels to various countries and he treats people with PTSD. I think he is based in Troon when in Scotland, and Calgary, Canada. I do think he may be semi-retired and does the travelling work as part of his retirement. His specialism is myofascial release.
From what he said, the IBS could indeed be caused by skeletal alignment. I had one version of it for years until I had chiropractic treatment. My chiro also identified one version as caffeine triggered (not just coffee).
I notice you mentioned that there is a group in Edinburgh offers myofascial. I think that may be the same link I also sent to CG, so that is interesting.
I hope your pain has been less over the festive period.
Fx