Following the completion of the first panel on the bench I made a simple mould and cast in the backing with fine aggregate and cement then weighed it down for a couple of days to ensure the face of the mosaic would be perfectly flat.
After two more days the panel is taken out of the mould, flipped over and cleaned (below photo)
The steps have already been laid with a void ready for each panel. Photo below shows first panel installed, pointing still needing to be done (interesting how the colours look so different from those taken under the studio lights to those in natural light)
This photo below shows the first installed panel looking down the steps.