I've been looking online for replacement coals for my gas fire. I want not just the coals but the "thing" that they rest on and also there are two upright "things" that the coals lean against at the front of the fire. I'm sorry but I've no idea what to call these "things".

Two problems... (a) I can only find people who sell replacement coals, not "things"; and (b) I gather the coals should be as recommended by the manufacturer. The manufacturer is Ashleigh and the fire is about 20 years old. I'm struggling to find a supplier, can anyone help please?

I had your problem, and could only obtain requirements from the manufacturer, (not Ashleigh) at an exorbitant price.
The coals and the ceramic radiant bed were specific matches and placements to get the required gas mix for correct flame burn.
At around £100 it may be better to put it towards a complete new unit, after 20 yrs.