Humphrey - I'm sure the physio will tell you the same but try to keep your knees together as much as you physically can (hard when you're walking!) - so when you sit, turn, stand up, pretty much everything bar walking.
I have tried to find a video of the technique my osteopath used on me, that I could do myself a little but have failed so far so will try to describe it for you. It really does help, I promise!
Lie on your back with your feet hip width apart on the bed and your knees bent up to right angles(ish). You won't be on your back long, don't worry.
1. Place your hands on the outside of your knees/lower thighs, and push your knees together at the same time as using your outer leg muscles to pull your knees apart. So you're creating resistance in your thigh muscles. Do this manouevre for about 5 seconds if you can (You might want to get your DH to do it for you, it's easier with another person holding your knees) then relax your leg muscles before you let go with the hands.
2. As soon as you release the outer knee, place your hands on the inner knee/lower thigh and push outwards, at the same time using your inner thigh muscles to try and pull inwards. Again for about 5 seconds and again relax the leg muscles before you let go.
3. Then repeat 1. again; and then repeat 2 BUT after the 5 seconds, suddenly let go with ONE of your hands while still using your inner thigh muscles. Your knee will bounce inwards, you might feel a sudden crack (this is your SP going back into position).
Then do it ALL again but next time, release the OTHER hand quickly at the end. If your SP didn't crack the first time, it probably will this time!
It can sound like a gunshot if it's a good release, other times you might not hear anything, or even feel anything, but it will still probably provide relief.
If that doesn't make any sense, or you need more explanation, I'll try and make it clearer. If your SP is well out of whack, it might hurt a little to do this to start with, and your muscles might feel too weak to put much pressure on (I found that when it was very bad, one leg would be too weak to do a good job) - this doesn't matter, the manouevre should still work so long as you get some pressure. If it hurts TOO much then please don't do it, of course. And if you start to feel dizzy, sick or faint at any point then STOP immediately and sit up, or roll over onto your side (knees together of course). You may find it easier with a pillow behind your upper body to help you reach your knees but the flatter you are, the better, so coercing someone else into helping you is a better plan. :)
HTH!