Cabriolet Flat Battery issues

[matteyre]

Hi, does anyone have any tips for this problem...
55 plate S4 Cabriolet which has been parked up over winter
Flat battery, no red flashing lights on either door, and doors wont unlock manually with the keys.. keys turn both ways but no response... although the boot will unlock. I have tried attaching a trickle charger to the 12v cigarette lighter adaptor in the boot, but nothing so far...
Have the keys stopped being recognised by the transponder, or is it just that I need to get some charge to the battery for the central locking to override manually?
Is there another way to open the bonnet and charge up that way.. obviously cannot access bonnet release as things are..
all help gratefully received,
Matt

 

[hades-]

you should beable to open door with key
that doesnt need any charge in battery to work

 

[matteyre]

you should beable to open door with key
that doesnt need any charge in battery to work

you would think so, but it doesnt do anything, turns both ways but nothing happens ..