I need to remove a flat battery from an Audi A4 1.9 TDI. I have removed the top plastic cover and unscrewed the terminal connections but cannot figure out how to get the battery out of its bay.

There seems to be a screw between the firewall and the battery which needs a long allen-key type of tool to unscrew. Can someone tell me if this is what needs to be unscrewed to get the battery out and what type of tool I will need to use.

Thanks in advance,
Russell.

 

I need to do this too, the allen-key is too deep to reach with my standard tools. Is this the only screw that needs to be removed or is there anything else that needs to be done?