Child-safe window check reveals unauthorised changes in bathroom.

I have recently joined the Strata Committee of a 1983 built Unit block in NSW.

The Child Window safety device installer has reported that the bathroom of one of the Units in the strata probably some time ago appears to have had a renovation carried out on it, resulting in the bricking-up of a little more than 1/2 of the window sill to the upper level of the window sill, and a shower recess only of about 900 x 900 installed in lieu of a bath with shower hose as noted for all the other units.  

The current shower area (abt. 900 x  900) abuts the wall where the window can open (slide), and the window can open (slide) up to ab. 80Cm. 

Unfortunately with the bricking up done on a little more than 1/2 of its length it is not possible to install a “Child Window safety device” that would be able to restrict the opening of the window to 125MM, as nothing can get in between the Window track and the bricked up section of the window sill.   

The space between the rear of the bricked up section of the window sill and the Window slide track is only about 3-4 Cm.

If the Bathroom window gets broken it is unlikely that the window could be removed to be repaired.

Preliminary indications are that there is no record in the Strata that any approval has been sought / given for this bathroom change and to sort this out will likely mean the fix will be after 13th March 2018 (unfortunately), and could be a problem and expensive for the lot owner.  

Has anyone else encountered such a situation ?   Any suggestions would be welcome.

To me it appears that the facts of the matter need to be laid before the Lot owner, and will likely result in the covered in window area needing to be removed.