Composite door lock

[Tally101]

Hi
I want to change. a door lock on a newish composite door but after taking the handle off the lock looks to be in a metal shroud which has some sort of security screw on the front , my others didn't have this and the lock came out ok. how do I get the lock out of the door do I need to unscrew the security screw some how
thanks

 

[crank39]

Think there's 2 types, picture would help

 

[Tally101]

This is the lock.

 

[crank39]

Yes just undo and remove

 

[Tally101]

Sorted thanks