battery is at the front of the car in a DA... although the grommet you refer to is in pretty much the same spot as the DC2/4

there is a very hard to find blank grommet just next to the charcoal canister (round black cylinder) it sits just under a small bracket so you have to get the right angle to see it. If you are only using small gauge wire you could run it through the same grommet that the air con condensation tube comes through, this sits just under the charcoal canister.

another option I have seen, again with small wire is to run it through the boot where the speedo cable goes through. this means cutting a small hole in the boot and just push through.