Looks like the culprit is not the parasitic drain - as it flickers down to 0.00.Yeah my meter only has a single (auto) amp measurement scale, I don't really think the unit is accurate enough to be taken as a true reading, it does flicker to 0.0 intermittently also. This was why I tried (unsuccessfully) using the multimeter, I've ordered some replacement fuses so will try again. Maybe disconnect battery, bridge with a jump lead, attach meter then remove jump lead. I think this should prevent any spike which would blow the fuse but also allow me to leave the van locked as the alarm shouldn't sound?
Agreed with what @DaveD mentioned that parasitic drain would rather cause "long term" issues.
Before your fuses arrive if you want to experiment, you can "amplify" the current by looping a cable around the clamp. 3 rounds = triples the reading, etc.
In case you're planning to keep your van and do things by yourself - VCDS diagnostic tool besides just reading fault codes, it takes advantage of van's own sensors to monitor what's going on under the bonnet. E.g. see some related graphs ---> Which Jump Starter?
PS. I suspect there would be helpful information in van's fault memory. Even a Carista would help reading those.