I got bored and started to take the key apart - wasn't the best of ideas....
The key is sealed together, the only way to open it is to gently prize it open by going round the edges with a flat sharp blade, but it means you are cutting the plastic, so it would require supergluing back together. I didn't open it all the way though, but needless to say, I made a right hash at it, and have chewed up the edges of the fob when trying to prize it apart.
My imobiliser wierd looking glass tube thing HAD come loose, so I clipped it back in place. I've lost alot of the recoil action on the flippy key, but I could probably fix that if I got some needle nosed plyers and turned the spring another full rotation.
I need a new key anyway, so I'll be keeping an eye out on ebay, and I'll slice the new one open with a very thin sharp blade, and make a neater job of it second time around!
So, lesson to be learned today is... If you want to open your key fob out of curiosity to see whats inside it..... DON'T!