Help!!

[Simon Wallwork]

Came back from two weeks holidays to find my FL S8 (D2) completely dead electrically.

Drivers door opened on the remote, but alarm sounded (weakly) and car wont start.

Cant unlock the boot door to charge it.

Looked on here and found advice to connect charger positive to batt lead on pass side kick panel. Tried it on thick (batt?) cable and on the red connector to its left. In both cases relays started chattering, and I grew afraid of damaging the car. Lights on dash did come on though.

What to do?