Render board battens/steel frame

[Nessie]

My timber frame house now has concrete blockwork completed as far as it’s possible to go due to dormer windows and other design. The house will be getting rendered so I now need to attach render boards to the same depth as the blockwork (50mm gap + 100mm blockwork).

Can anyone recommend a system for providing a framing system, attached to the outside of the OSB of the timber frame, to give me the required depth to attach 12mm  render board so it’s effectively flush above the concrete blockwork, ready for the whole house to be rendered? Thanks !