Euro cylinder cant see the removal screw.

[beerboy]

Afternoon, I lost the keys to our French doors, I ordered a new set and replaced the LH ( 3rd picture ) lock. However the RH door has an extra plastic section that does not seem to be removable. There's a metal plate as picture that I have taken off but there's nothing behind it.
Is it possible I need to remove the glass to access the screw.
Thank you for looking

 

[Wayners]

If it's definitely not on the door edge then it's behind glass.

 

[beerboy]

Thanks hopefully the glass isn't stuck in with tape, as the glass is fitted from outside.

 

[crank39]

The extra plastic section is called a flying/floating mullion and in does need to come off in order to expose the same sort of locking strip you see on the master door, if there are no screws up and down the mullion(usually 4 or 5) then they are on the glazing side which will mean the glass has to come out, however it's very rare to see this but you may the rare exception. If its any consolation then the slave door cannot be opened when the master door is closed as it overlaps the slave