My aunt who lived in Grendon Road, Kings Heath had a Triplex grate like the one in the first photo. I don't know when the house was built but the Council must have had these grates put in all new houses at that time. The tiles in the top were deep green, with a steel screw or whatever in the middle of the four tiles. I don't remember her ever using it for cooking, as she had a gas cooker in the kitchen. My gran also had one, I don't remember as much about that one, oddly, as I used to live with her, but the tiles may have been deep blue on that one. I remember her using it for cake baking though. I think it took a specific sort of skill, as she only used to put her hand in the oven to see how hot it was/was not and then the cake used to go in. No scales either, so it was all really hit and miss, but it was all hit, as nothing ever failed, apparently. A nice trip down memory lane, thanks Stitcher.