Has the bottom dropped out of your chimoniere ?

I think that’s what they are called, you know, those large spring onion shaped outside heaters.  Last night I sparked ours up to warm up the orangery prior to going for a swim in the pool.  Some few minutes later the wife shouted “ Fire, fire “ and pointed back to the house where clouds of smoke billowed from the orangery.  Galloping back to the House we discovered that the bottom had dropped out of the chiminiere and had set light to the wooden flooring just below it.   When it had cooled off this morning I examined the !Removed! thing, only to discover that amongst the ashes there lay a perfectly round and symmetrical piece of iron which was a tad smaller than its counterpart inside the bottom of the spring onion.  This made me wonder if these heaters come with a whole in their bottoms and a covering plate, perhaps for emptying.  Anyone got any ideas ?