Front trunk and jumper cable issues

[koosh]

Ok so my boxster has been laid up for a couple months now since I swapped cars, I stupidly haven't been periodically going and starting the car nor did I disconnect the battery as I didn't expect it to be sat for so long.

Today I went to try and get the car started and I was unable to get into the front trunk. I googled and searched and so forth and ended up with both front wheels and inner arch linings off but I still couldn't find those little hooked cables (the rear one is there however and it works) and I also tried the jumper cable on the little red tab in the fuse box attached to a spare battery but as soon as I hooked up the second positive to the battery the alarm sounded and I got no response from the switch in the panel by the seat.

I am not sure if the battery is so dead that it needs a few minutes connected up? Also I Pressume this procedure bypasses the installed battery alas it should work regardless of the installed batteries health? I need to try it jumping off a battery installed in a working car so I know it's good but other than that I am stuck for ideas other than an axe through the front trunk and a second hand unit to replace it..... Really don't want to do that though hahah!