Sorry i think you took that the wrong way mate, all i was trying to say is they are hard to get on in the wrong order anyway (yours being spot on), but even if they were forced and put on the wrong way it still wouldn't affect anything.

Just trying to help you out.

The pipes inside the black sections are metal, and could well of been bent or twisted before you got it and therefore be blocked. Its very common for the injector clamps to snap and before youve realised youve ended up twisting the pipe thinking the nut is seized (not saying you have but i have done this)

Have u tried removing the pipes and blowing down them to check if they are blocked?