Battery charger lead

[Pete C]

I want to add a permanent battery charger lead to my starter battery. The problem is that there are no threads left to attach it to the usual place due to my towbar installation (see picture).
i thought about using the clamp bolt thread behind it, but I can’t work out what thread it is - it’s not M6.

So 2 questions:
Is there somewhere else close to the battery that I can attach the positive lead ?
What thread is that clamp bolt ?
Thanks,

Pete

 

[Higgidav]

I just connected mine to the other clamp bolt.

 

[Pete C]

I think I’m going to have to do that, but would prefer to put another nut on top of the existing one.

Pete

 

[travelvolts]

I would connect where all the other wires are and have the cable facing to the other side.