I read somewhere that FeCl can be used to etch stainless steel, so I decided to give it a go. First of all I transferred the design to a piece of stainless.
I then turned the hob on and applied gentle heat. Which seemed to work.
Unfortunately I then applied not so gentle heat and the pyrex dish shattered. Ooooops.
After shattering my only pyrex dish I decided an alternative approach wad needed and used a plastic dish with water in it. I warmed the water every 15 minutes in the microwave (removing the container with the workpiece and etchant first).
I kept this up until I noticed that some of the resist had lifted so I stopped at that point. Inspection of the workpiece showed that some etching had occurred but not much before the resist lifted. I also noticed that areas touched up with a etch resist pen (from Maplins, I suspect its a regular fine tip permanent marker) had come off the workpiece early in the process. I tried a couple more etches on stainless but found the same problems with the resist lifting. The photo below is one of the stainless pieces with after covering with permanent marker and abrading with the rubbing block to expose the high spots. This demonstrated that the approach may work.
The next photos show my most successful approach.
First of all I taped the press and peel to a piece of brass with the tape on the back of the workpiece.
For this etch I modified the warming bath slightly by raising the container with the etchant in so the warm water touched the base of the container as well as the sides.
Three hours of etching (reheating the water and agitating the solution every fifteen minutes or so) produced two well etched pieces with no lifting of the resist.
I now need to cut the badges out and then possibly nickle plate them before painting and sanding the paint off the high points.