As others have said, the fact that the gauges mist is a feature of simple sports cars. Warm air inside the gauges meets the cold surface of the gauge and the inevitable result is condensation.
As for the flat spot, I don't believe it's a good idea to keep a new engine below any artificial rev limit. It needs to be progressively run throughout the complete rev range as Chris describes, right up to the red line, but shouldn't be allowed to labour in any gear.
If it were my car I'd give it a good workout for a hundred miles and see if the flat spot remained, and if it did, take it back to a Morgan dealer.
