The Franke Basel Tap Valve 1427R
Nut Height: 8, Splines: 28, Overall height: 53mm, Diameter at thread: 21mm
If, when you remove your Valve it looks like this then your Brass Bush is stuck to your Valve. If you cannot separate it, then you will need to purchase the Franke Basel Tap Brass Bush as well (one per Valve) as you need this part as well.
For tips on how to separate a Valve from a Brass Bush, see here.
BREXIT: No additional charges on delivery once your Order before shipping charges is less than £135.