My 12v battery for van is between the two front seats in the console. Can I trickle charge it via the jump start point under the bonnet or do I have to connect directly to battery. My van has been converted as a camper and has hook up and I would have thought I could trickle charge using this route but appears not. Any advice would be greatly appreciated. The battery was new in summer and is the correct one. 

Yes, can be charged from there.

You can also wire it into the leisure battery system if you know what you’re doing but you can’t charge leisure and vehicle batteries together on the same circuit, each battery has to be isolated from the other.