Forgot to mention - I do the double chin exercise on the website, which was the one the physio prescribed.
It's REALLY unattractive (don't ever do it in front of a mirror, I discovered I could make it to about 7 chins! ), but it's very effective. I was told to imagine that my head is a drawer, and i'm sliding it slowly backwards, back into the dresser. Keep everything in line - shoulders back, abs tight, head upright - the only thing moving is your neck slowly going backwards.

I'll shut up now!