Right, time to bump this thread up again as we have some major progress now. I've just taken delivery of the first heat shield, along with a fiberglass version for me to make final adjustments, to get the most out of the design/shape.
We are going to totally modify the alloy plate too as the original one was overly complex and didn't do a particually great job. Here are the pictures of what we have so far. The finish is literally perfect and 100 times better than the original I had. I'm very happy with the way they have turned out.
As with everything, it will have to be tested before I sell any.
If anybody wants to take part in the testing I'll discount the panel by 50% for your time and effort. I would do his myself but I have used my car once in the last 3 months, so it may take a while!