The Grohe battery does make a solid impression when they are unpacked, mounted quickly, fits comfortably in your hand, works just fine - and looks surprisingly good, much more stylish from the pictures.
The assembly is no mystery to - 2 things one should consider when you have never exchanged a fitting: for sealing the drain valve plumbing putty is required (eg Plastic Fermit) - so secure previously or in your order at Amazon. And: After the provisional adjustment of the linkage for raising and lowering the end closure, the two operating rods have to be shortened - a sharp Puksäge or a hacksaw should therefore also be in the toolbox.
Next time I buy a Grohe same battery ...