Personal if I was going for a folding pedal and would have to use it in the wet I would not consider the MSK 7 but would go for designs like the welgo 147 which you can get in metal bodied version also by user makers. Ie religh stomp. It folds as quick but is a stronger pedal in my experience with no grip issues.
Else, anyone done anything to double cage the Brompton folding pedal?
That would be a fit once and forget solution.