Door handle!

[Fredben]

Hi all,

The external handle to my front door fell off when closing. It does not fix back on. Im guessing a fitting has gone missing but do not know what exactly. Also I’ve been unable to remove the handles & plate. Am slowly driving myself insane trying to resolve before conceding defeat and calling a professional.
I have attached pictures of the handle/lock.

 

[Notch7]

Is that a Hoppe Atlanta security handle?

If so I thought they had 2 visible screws on the inside.

 

[Fredben]

It doesnt say make of handle anywhere that I can see. Only has the secure by design mark on handle. There are the two screws on inside plate but have unscrewed these and very little movement in plate/handle.