Thing is about the PTJ is that it's only showerproof which is most of what you get in blighty anyway, and because it's only showerproof, it's more breathable than any waterproof hardshell, so less sweaty boil-in-the-bag rides. If one does need protection from a downpour, a light waterproof shell is useful, also useful if the temperature drops at night. So rather than being a drawback, lack of waterproofness is actually a bonus.
Thing is about the PTJ is that it's only showerproof which is most of what you get in blighty anyway, and because it's only showerproof, it's more breathable than any waterproof hardshell, so less sweaty boil-in-the-bag rides. If one does need protection from a downpour, a light waterproof shell is useful, also useful if the temperature drops at night. So rather than being a drawback, lack of waterproofness is actually a bonus.