OK, here's where my art degrees and years of color theory can finally be useful in restoring British cars... wait, that's overkill. Actually, I've been looking for paint to paint my wheels too. Mine are rusty because they wore trim rings for decades, but the previous owner took them off and lost them before I bought the car.
The original silver paint is quite a bit darker than the "silver wheel paint" at most auto parts stores. The modern paints all try to mimic aluminum wheels, which is a brighter shade of silver than the original silver on British car steel wheels. I found a Rustoleum silver paint that is about right, but it's slightly too pale too, really. The opposite extreme is that there are lots of metallic gray paints that are too dark. I'm still looking.
Has anyone compared the silver POR-15 paint to the color of our wheels? The images I can see on the web look like it might be a match, but color matching is almost impossible on the web. (That's one thing I have experience with, color matching software and hardware.)
Scott