fitted by VW
i broke a van with a split charge fitted by vw and it did not use a relay like that!
inline fuse (fuse holder stamped vw) , front to rear wiring went under the van (double insulated) all with grommets , much bigger physically and rated BOSCH relay ( 80amp from memory)ect
it was all intergrated with a twin electric towbar system
yours defo dosent look vw fitted , but it may be dealer fitted if they called a sparky in , subcontracted like