I finally got a letter through from my midwife; not with an appointment for the Physio, but telling me I had to book it myself (the rules have changed apparantly) and a list of what to do and not to do throughout pregnancy when you are suffering from SPD.
Here are a few of the main pointers from the midwife, some of which I do anyway:
wear pelvic support belt
use crutches to walk, if very painful
reduce time you have to stand or walk. Don't stand if you can sit, don't sit if you can lie!
take shorter steps when walking
avoid straddle positions
avoid standing on one leg
do your pelvic floor muscle exercises (see PFF 'app' review)
place a pillow between your legs when sleeping
when standing, tighten your bum muscles together as hard as you can for 5 seconds. Repeat it 10 times a day, twice a day