S8 Ingiter

[homer simpson]

Hi all. My N/S xenon does not work so I decided to change the bulb - nothing. I managed to put it back together but it was very difficult, the igniter just about turned right into the closed position.

So today I decided to swap over the igniters to eliminate them as the fault. I took the O/S off but I cannot get either of them back on! Is there a knack to putting them back on? I have lined it up, pushed in as far as it goes and it seems flush but it will not turn to lock into place.I have tried to make sure the metal locking spring clip is out of the way. Help!