I didn't replace the binnacle top, but I did replace the fascia, see photo below. All the holes drilled previously in mine had been in way of the black or grey plastic instrument panel originally fitted which was given the elbow, and I made a new one from a sheet of half inch ply. It's not the prettiest fascia, but it's vastly better than what was there before.
Ps. Sorry if the photos appear upside down, don't know why that happens, but they start off the right way up, turn upside down in the posting, but come out the right way up when I open them on my iPad. Maybe there's some Southern Hemisphere software in there somewhere !!