worcester 24si

[CXR100]

Went out to this boiler tonight, just a service , noticed the flue looked like it wasnt pushed home all the way if you get me, undid the jubilie and tried to push it down but it wouldnt go, turned the elbow to find a lug stopping it, never fitted one of these but it looked like a propper poor design , took the casing off and inspected from inside, the inside of the fue didnt look like it even line up correctly with the fan outlet piece from about 10mm , no seal at all , and just looked like the flue elbow and the spigot on the boiler butted up againt each other, and the outed flue the same, can anybody confirm that this is how is should be. Thanks