Trev don't throw the towel in just yet,
You can replace the splitter yourself, take a look here,
www.actmeters.com/440-Tamper-Splitter
Me give you little advice mate, chances are engineer won't have splitter on van, he do some meter checks and remove splitter and wire tampers into global,
The splitter is there not just to identify which lines the tamper is on, it's probably fitted for a very good reason, it could cause falsies if removed.
It's an easy swap, mains off, disconnect battery,remove and refit one wire at a time.
e manno, October 2012