The aerial on my sons N15 Pulsar has snapped off, so i am trying to replace it. If i remove the retaining screws on the roof i can pull the plastic cover up and un-clip the black electrical cable but the rest of the unit feels like its held pretty firm in place by the clearish tube running down the A pillar. Can anyone please help shed some light on how its held in to the A pillar and how to remove it?