How do you UNLOCK valet mode on a 95 Jaq without a key and the battery is in the trunk?

This just happened to me. open the "bonnet" of the car, and on the passenger side, closest to the dashboard, there is a "positive" point, with a black rubber cover, where you can place the positive end of the jumper cable and attach the negative to any part of the car. Once you give it a little juice, the trunk can be opened, and you can then get the battery charged the normal way.

It took us two weeks to figure this out. LOL