New tap jet streams water out

[JayUK20]

I just popped on some new lever tap heads and cold pours as it should but the hot comes out like you've put your finger over one side instead of flowing out nicely.

I checked under the tap arm and there doesn't seem to be a blockage.

 

[Burnerman]

There's often plastic inserts screwed into the end of the tap spout....has yours, and if so can you unscrew it for cleaning?
John