I have no solution as I can't say it bothers me too much as it's the Rev counter I'm interested in and that never steams up, just the oil pressure gauge does normally. I can fully understand if it does annoy you though.
My only observation based on ownership of three different models is : - If you store the car overnight with the roof up or the tonneau fully over this phenomena does not occur in the garage where my car calls home, so I find this no hardship as a remedy for a little irksome problem - typical Morgan ownership a little compromise.
Stored bereft of a cover is guaranteed misting in the winter.
