I had exactly the same issue when I replaced the systems in my console.
The main face was full of odd holes that didn't fit any of the new gear, so my answer, like Biffs, was to cover over all the existing holes with a piece of new material, and in effect start with a clean sheet.
I've actually done this twice over the last few years as I was never really happy with the cut edge on my first attempt.
I found an off-cut of Black Plastic at a sign makers that has a nice leather style embossed finish, cut it to size, screwed it down onto some sealant and cut the new holes through the new 'dashboard insert' and the original face of the console.
It's obviously not pretty from behind, but looks good from the front.
Best of all it cost me just a couple of quid for the off-cut that I've now got two inserts from.
The stainless Box section along the top edge has been added more recently, firstly to hold the front edge down more securely so the rain doesn't go down the back, and secondly as I have another project in mind that will use it as a mount.
RIBBED For extra pleasure.
Member of the ebay Blue RIB cover club.
Member of the Bombard 380 Aerotec club