I would assume that it's clearly physiologically easier to recover from a vaginal birth with SPD than with pelvic surgery that c/section requires. (so therefore studies are a bit moot yk?
Not necessarily. It depends on what position you've been in and how long the pushing stage is. It's the pushing stage that damages the pelvis. It's perfectly possible to have a very long pushing stage in a bad position that results in a much longer recovery than a caesar ever would. My first birth being a case in point.

Thanks for the information about your different births Inanna. It's heartening to know that one long one does not necessarily mean other long ones. Though I don't like being reliant on midwives listening to my wishes that I want a caesar after 20 minutes.

I'll have a think about the water birth scenario. It's just a pain that yes, although I have time up my sleeve, I will have to change caregivers from private ob to a birthing centre if this is one thing that I want to consider.