After looking through about 1,000 different medals, honours, decorations - royal, noble, military, civil etc, etc, with no luck at all... I then had a really good look at the item and sketched it to separate the different parts. It's not a crown in it - it's just two mirrored swirls with a diamond sitting on top of them, that are sitting on top of the Iron Cross (not Maltese Cross). That tends to signify either Prussian or German design. The fleur-de-lis then confused it, which is mainly a French design, but has been used on English medals and shields as well. And it can also signify a 6th son in English heraldry.
But you know what folks, when you have a good look at the actual casting job - it's terrible! And I have a feeling this might just be a project of someone who did cast iron works (or was learning it) and wasn't very good at it yet! Look at the different "feathers" beside the Iron Cross and the strange extra bit hanging off the bottom one on the left hand side, that's not on the right hand side. The feathers are not uniform either. And look at the gap between the right hand and bottom sections of the Iron Cross - it's all filled in there, and the opposite side has a rod going through it - and I don't think it's deterioration - it's just badly cast.
So I'm putting it down to an apprentice's cast iron work project, and doubt we'll be finding it anywhere online - or I'll be very surprised if we do!
Does anyone else agree with my assessment?