Welcome to the forum.
Taps, both sink and w/h basin can be updated for a new one, either a domestic one or one designed for caravans. If your van has internal switches then domestic ones will not work. The two problems to cope with ate accessibility. and linking the tails to the existing plumbing. Easy when you get the right conversion fittings.
If you try to change for the original, you will often pay a large premium for no real advantage.
This is often a cheaper and better option than trying to fix an old one. IMHO
John