It can be a common enough problem that when you remove your Valve it looks different than the valve in the picture. It is most likely because the brass bush is still attached.
Here is the 1427R Valve (used in the Franke Olympus Tap and many other Kitchen Taps):
Here is the same Valve stuck inside the Brass Bush
If the Valve is stuck inside the Brass Bush then you will have to separate them OR buy a Brass Bush as well.
Please note that there is an EARLIER version of the Olympus Brass Bush and we do not stock this version.