[Arran]

Actually you could try patching the area where the hole is, one good thing about burl and stump walnut is that it has an irregular grain so an irregular shaped patch would be hard to see. I would plug the hole with a piece of hardwood dowel or a plug, and put a patch on the inside of the cabinet so it can't be pushed through.
There are at least two methods to patch the veneer on that panel, one would be to make the patch first tape it over the area where the hole was, and then trace around the outside of it with a razor knife. The other method is to tape a uncut piece of veneer over the area you want to patch and cut through both the new veneer and the veneer on the cabinet at the same time, I use the first method myself. Once the toner covers it all you would never be able to see it.
Regards
Arran

P.S Actually in looking at the marquetry of the front panel you could probably get away with using a straight sides patch running between the edge banding and the dial escutcheon, It's stump or crotch walnut I believe.