Just an update. Honda have said that the hole in the crankcase should have been cleaned up at the factory. They assure me that the engine will still operate as it was designed to do.
They offered to clean up the hole, though I passed.
What I don't agree is that it should not have been there in the first place. The other G200 engines I have seen don't have a hole. I believe it's a fault in the casting process.
