The key one mine was quite sticky for quite some time, no amount of grease, graphite or swearing would loosen it up. It was a massive pain every time I wanted to remove the seat, so I tied a cable tie around the little u bit with the tail of it poking out just above the licence plate. Now, when the key doesn't work first go, just put hand up it's bum, pull cable tie and voila, seat pops off.

Sadly, I swapped my bike for another (Husky te610), but strangely still find myself coming back to this site and reminiscing about it.

Oh, and Kenny, if you read this, hope the bikes treating you as well as she did me.