Replacing bathroom door handles with short plate

[bolo 2]

We have 3 bathroom locking door handles which need replacing but which are apparently no longer available.. The backplates shown in the photo below are 11.5cm long and 4cm wide. I have 2 questions: 1. Are these still available, and 2. Is it possible to do a complete swap with freely available longer plate handles?

 

[Wayners]

You can buy handles that are big enough to cover old holes.
If you get fixing trouble with existing holes use through bolts not screws.