My first thought for his outfit was to sew shiny/silver thread into the fabric of the shirt and pants, you could control the pattern but it would be very time consuming. Alternatively, some of the US fabric chains sell "sparkle mesh" that would be perfect for that kind of frost effect, either tacked or glued on. The mesh pattern looks kind of like the tiny veins you see on leaves, very organic, not a straight weave. I assume you might be able to find something similar in the UK, though I don't know where to look.
Photo of silver sparkle mesh: http://4.bp.blogspot.com/-QW_wAuCwjl...0/IMG_3484.JPG