How to Remove Speedo Glass - Keeway 125

I have recently bought a Keeway Superlight 125cc. The glass on the inside of all of the dials is dirty - it looks like it has been wiped with a dirty/greasy rag leaving smears. Can anyone confirm, do I prize open the dials by lifting away the bezel at the 'top' of the dial housing or are there screws on the 'inside bottom' that need to be removed by dis-assembling the dials?

Before you go and snap something off , what makes you think these clocks are designed to be prized apart ? Having said that, and having looked at some pictures, I reckon I would start by removing any visible screws from the back to get a look inside then take it from there. If the back covers come off you should find a plastic "skeleton" that the fronts are probably also attached to . They have to come apart I guess or there would be no way to change the bulbs but the parts diagram suggests that the clocks themselves are sealed units .