garden wall/shed

Hi guys, this is my first time on a forum so go easy on me.
Hopefully you'll be able to help me. I'm sure the answers will be obvious to you professionals but as a joiner/sparky I need help.
In a couple of weeks I'm going to be starting on my garden project, first job is to remove old fence from 2 sides of garden and replace with a block wall, then render garden side and paint other side. My question is this, what blocks to use?
The side wall is 10m long and back wall is 7.5m long, hoping to go 2 meters high if that's possible without planning permission. I was thinking of doing 600mm × 600mm footings and using 8"x8"x16" 7n hollow blocks with pillars every 2040mm. Pillars would be either 16"x16" or 12"x12"(which I'd prefer). Was thinking of putting 10mm re-bar in full depth of footing to top of wall in each pillar and then fill with concrete. Would these blocks be suitable for this purpose, really don't want rendering to crack. Appreciate any help/advise, Thanks

 

Just checked and it is 2 meters maximum without planning. Thinking about it I'll probably only go around 1.8m.
I'd only be filling the 6 pillars with concrete. Does this sound a little overkill? What would you guys do?

 

There will be in pillar in the center of the 10m wall so was going to put an expansion gaps where the wall meets the pillar, can u get any ties that move like sliding ties? I'll be putting stone capping around the top of the whole wall. With it being rendered I'd assume I'd need some sort of dpc? Does this not weaken the wall at all as surely the blocks don't bond as well to the dpc. Could I just use 2 or 3 courses of engineering bricks instead? What's your thoughts please, thanks