Code needed for my Grundig stereo please?

Hi, damsel in distress here.

I just spent ages removing the Grundig stereo from my old Corsa to get the serial number, with the hopes of getting a free code for it after a disconnected battery sent it into safe mode. Only, when I input my serial number it just says code unavailable. :(

If anyone could help me without me paying out the £20+ that Vauxhall will charge I would very much appreciate it. If not I'm just going to have to buy a new stereo as I'd rather pay the extra and get an up to date one rather than paying money for the code.
Thanks. Lisa. :)

Grundig CAR 200 (D)
GM0200X7384111