Leaking bathroom tap/mixer

[Brfc]

Hello
I have the following product in my bathroom

Grohe Eurosmart Cosmopolitan Bath Shower Mixer - 25129000
The tsp is constantly dripping, I attempted to see where the leak was coming from, couldn't see anywhere I open the tap up.
So unscrewed the shower connector and noticed the water then started dripping from there.
but I dont know how to open this any further, I see no holes or any bits where I open this further
any help will be appreciated

thanks