Hi Ian and welcome to TM
I believe the speedo over one side is historical on a Morgan, I am sure MMC would swap speedo and Rev counter around in build. Or they might do what you want with it behind the wheel.
I have driven my Roadster in some very heavy rain, initially I had the odd dribble from the header rail.
They can let a little water in but nothing like they used to, the hood rail seals very well if adjusted properly, with the use of a little neoprene and D seal around the side frames any leaks/Drafts can be eradicated.
