Update on this after a "test" last night. After going from junction 9 to junction 11 of the M4 (12.7 miles) in very heavy rain at high speed there was slight dampness above the hood rail but nothing that would be noticed without putting a hand up there to feel it. My conclusion is that the distortion of the rail as it is now is of no consequence so I don't propose to strip it down just to fix that.
Thanks to those that responded and for the hood related diversions
Dave
