If I want to split the chain, how do i do this. There seem to be two chain rivets that are prouder on the outer plate than the others, do I just push one of these out?
That joiner looks like the KMC design used on their single speed chains.
The back piece has the two pins permanently fitted which need to be bent towards each other to release the thicker plate with the two keyhole slots.
Then persuade to outer plate to come off whilst keeping the link bent (this is the tricky bit!).
Technique I use is to get the link near to the sprocket with the chain very slack, stop the wheel turning, bend the link with one hand by pushing against the sprocket and pick the plate off with a set of long nose pliers.
Tomsk had one of those plates vanish on the Horsepower helpers ride (1/8" version of chain) after fixing a puncture at Newmarket - symptom was a clicking every second (ish) crank rotation under load, we never figured out how the plate escaped, they are a pain to remove!
I prefer the traditional joiner design - three piece version with the separate spring clip holding it all together - a lot easier to dismantle when you want to.
Single speed chains use the traditional pin, bush and roller design whilst derailleur chains have a drawn section on both inner plates that replace the bush which gives more sideways flex - the design was first used on the Sedis Sport chains (in the 80s I seem to remember).
The different design does have implications for how chain lube enters/exits the chain - you need to get the stuff onto the plates on single speed versions to lubricate the pin/bush interface, on derailleur chains the lube will find its way from the roller to the pin past the split bush.