It's a doddle to fit in a diesel heater and split charger
The difficult part is plumbing the heater into the van's tank, especially the newer ones. Some new regulation a few years back in the EU regarding plastic tanks, means that we have to fit vehicle specific standpipes, which usually involves dropping the fuel tank.
On my old 04 plate Citroen Relay, it was easy to plumb into the return to the tank fuel circuit with a tee piece as it ended at the bottom of the tank. On the next generation models, the return to tank fuel circuit ended at the top of the tank, hence why we have to fit an additional standpipe. I fitted the vehicle specific standpipe on my 62 plate Peugeot Boxer by integrating it into the fuel pump. I removed the fuel pump to do this, which was a lot easier than having to drop the tank.
Webasto also advised at around the same time that the universal standpipe they sold couldn't be used if the van's tank was plastic, only if it was metal.
When Grippatank fitted Daz's heater, they got caught with this on his Transit Connect. The heater would only run when his engine was running.