Can my front door lock be mended?

[ff33ww]

I have a grey grim looking lock on the front door of my flat. The closest in design I could see on the internet was the photo at the top of this page:

Google "gallery.hd.org/_c/office-motes/door-lock-Yale-mono-1-DHD.jpg.html?sessionVar=spider&sessionVarLocale=en_GB"

(except mine does not have those three visible screws).

After an attempted forced entry, the switch on the left seems to be unpredictable, so could end up locking me out. The small ?handle/knob on the right is loose. I know nothing of DIY. Does it sound like an easy mend or something that needs replacing?

Thank you.

[JT9563]

It would be easier & cheaper to replace it, the nibs on nightlatches invariably go after a while anyway. Parts for locks (with the exception of the most expensive ones) are like everything else these days, made to be replaced, not fixed.