Mothercare Convertible Highchair tray retaining clip

This is to replace the tray retaining clips on the Mothercare Convertible Highchair.
Product info here: http://goo.gl/Yks20

The pegs broke off our one which meant the tray could easily be knocked off by a boisterous child. I could fix it with epoxy and doweling but this gives me an opportunity to learn some 3D modelling, which in this case was using Sketchup.

This is my first model, so if anyone has some tips regarding making it printable, modelling techniques etc please get in touch.