I have fake jack hole covers on my car. Not sure if anyone else is going down this route or considering it but if you are this was what I found as solution.
Whilst there are knobs you can find on cookers that look similar to real thing they are way too big - the originals are actually quite small.
You can buy original repros but they'll cost 270 euros:
What I went with is approx same diameter as genuine and similar looking and it is......... a Stainless Drain Bung (yes really!)
Very reasonable at £8.71 each including VAT so £35 for a set.
The flange is bonded to the other side of the sill.
https://www.seascrew.com/browse.cfm?...S&l=0000001120
You could easily file the raised turn grip down to get closer to the oem if you wanted