There have been several threads on this Dimples model as it was ubiquitous back in the day. Of course, as you've found out, they no longer support this model and no parts are available anywhere unless you're lucky enough to find a used part that corresponds to what you need.
And coincidentally, I was talking with somebody who had that same model Dimplex as we also had one years ago in a motorhome. He was running into the same problem as you as he couldn't find any parts either. Dimplex simply told him that they no longer support or make parts for that model.
They too had the flame light out and also the thermostat wasn't working properly. They diagnosed the flame light as a control board problem. Dimplex told him that when they
did sell that control board the cost was around $250. Sheesh!
According to the service manual, they have you check out three things if the flame is not visible: 1) check wiring connections, 2) replace LED light assembly (again, no part available), and 3) replace the display /control board. So you may want to check the wiring connections before you order a complete new unit ...
service manual HERE
Here's the one of the most recent threads on it here on the forum ...happens to be in the Entegra Owner's Forum but same model of Dimplex ...they give some suggestions on what you can replace it with:
Replace Dimplex Fire Place in '15 CS B