[Arran]

It looks to me like the structure under the veneer may have expanded from humidity cracking the veneer on the surface. What is interesting is that it didn't crack so much on the curved part, because that is where the wood is normally under the most tension, it seems to be a common fault for these cabinets to do that on the curve above the control panel. In the photos it looks like someone may have had a go at refinishing the cabinet before as it's looks matte and the original finish was glossy like a piano. I think that no matter what you do the original veneer is going to crack again, exposing any fills you may make, the only permanent fix is to replace it, the top section with the bands is stump walnut, the bands are zebra wood, and the part bellow is quarter cut French walnut. The easiest option would probably be to find an empty cabinet without this problem, other then maybe Russ not too many of us would attempt to re-veneer those corners sections ourselves.
Regards
Arran