Topaz existing wiring set up - adding solar

Hi,
I am currently adding an extra 240 v socket to the other upper cupboard to power a Avtex tv ( next to 12 volt feed).

I'm thinking of also adding a small 100w solar panel next, on the front of the high roof with a bespoke faring for wind issues.
For now I wish only to get the correct cables and set up in place before finally going thru the roof and connecting up to batteries.

While I'm routing cables, can some one tell me what I should do in order to integrate whatever cabling is required with the existing charging system for 240 v. I know the zig 9 is in the bottom rear wardrobe but do I need to go thru this or other set up? 
I'm no electrican of coarse, but practical. 

I currently have a 90 amp starter and a 100amp leisure battery in the engine bay with I assume all original connections and breakers and cabling running correctly as installed back in 1994.

I have a secondhand pwm 30 amp controller standing by as part of the install.
Any guidance moving forward and tricks to utilise the spaces available would be fantastic.

Happy Easter hols to you all.

A '94 Topaz should be pretty simple to deal with - there should be no need to disturb the wiring for the Zig charger - it should co-exist quite happily with the solar controller.