Neostrahl Tap - how do i take the tap handle off the top?

I have a Neostrahl mixer tap, about 3 years old. The chrome is bubbling off so i want to replace it anyway, but it has started leaking. Water is seeping out of the top and running down the copper pipe into the cupboard below. I found a small grub screw in the tap handle which i have removed, but can't see how the top of the tap comes off now. I don't want to force it and wreck it completely if it's fixed internally somehow?