Stringers for 1.7m high staircase between decking platforms

[severnside]

Our house is on a sloped site, we are building couple of decking platforms to get some level garden area. We need to build external steps between two platforms (max height 1.7m), we would like to clad them with matching decking boards. 

However in shops and on internet I can only see max 4-5 steps stringers. There is one shop edecks which sells stringers with more steps but they seem quite steep (225mm rise, 255 going). Could someone help me source these. I can build the plan of internet but don't have time/energy at the moment to build my own. So I would prefer if something off the shelf is available.