I think(!) fuel will only pass through the metering head when the air intake flap is pushed down. So when the flap is shut, no fuel can get through.

Probably best to take the red pipes off at the head, then you can tie them out of the way and they wont get damaged. There are two ways to do this;

1. undo the hex unions that the pipes pass through. (This is the union between the end of the pipe and the injector). Sometimes the whole pipe and injector will turn, and you dont want that to happen. If it does, proceed to step 2

2. undo the little (8mm head IIRC) bolt that holds the injector into the intake spacer. This way, the whole injector will pull out, still attached to the end of the red pipe. One or two of the little bolts are a bitch to get at though IIRC. Bag up the ends of the injector so they dont get shit on them.

Hope this helps!