Paint recommendaiton for rear of blackbutt screening fence?

Hi all

I have a new blackbutt screening fence which is 12m long, and 2100mm high using 40x40mm vertical blackbutt battens.
This sits against the neighbours fence boundary ( northern boudary ).
I have painted the facing edges (southern) with cutek extreme.

I have the dilemma of what to paint the north facing blackbutt which sits above the neighbouring fence line
Its high and will get exposed to northern sun so I want to protect it.

Its not going to be easily accessible to paint - might have to use get a 2.4m high ladder to access or ask neighbour if I can access .
So I dont aim to do regular painting of this section long term.

So asking what would you recommend as a more long lasting protective coating for this area - ? Im thinking dulux weathershield or similar?

Many thanks
K