How to replace the Golf battery
This is the left side (same as the negative terminal, US driver side) bolt holding the connector block. This may also be holding down the battery box. I used a long extension and removed this bolt. The bolt head is green-ish colored in thes photo.
I am not certain that the connector block assembly must be removed. Perhaps you should remove the battery cover bolt in front of the battery and try to remove the cover with the connector block in place.
I have enough socket wrench extensions, etc. that removing the connector block was not a problem. In any case, the assembly is only moved a little in order to allow the cover and battery some slack room.