I've got a V&B bathroom suite with a soft-closing toilet seat. The seat simply pulls of two pegs on the toilet bowl but they are loose and I can see no way of tightening them - they simply disappear with no way of getting to where you might think there should be a nut. Anybody any ideas, please?

I have a less posh loo seat with something similar. On mine there is a rubber bung with a bolt through it and a nut on the bottom end. Turning the screw head compresses the bung causing it to expand in the hole in the pan. Doesn't work very well.
When loose the lot can be just pulled out. Too loose and the nut falls off and dissapears into the bowels of the pan never to be seen again.