What to lubricate multi-point locking mechanism with?

[RrogerD]

What should I use please to lubricate the 3-point locking mechanism on my aluminium external front door? I assume that it is the same as a upvc door mechanism.
I would have used grease but then thought WD-40 and then maybe, graphite powder.
Thanks

In hindsight,I probably didn't need to remove it from the door (maybe) :-/

 

[crank39]

Light oil like 3 in 1 or silicone based oils for main gearbox, for the key barrel use graphite powder

 

[RrogerD]

I put some light oil on the movable parts and replaced the whole lot. Sadly, it's still the same. It's the hooks that are not retracting fully and so catch on the frame as the door is closing. If I open it fast, then they seem to return ok.
Would this be due to the mechanism simply being worn out? It's about 15 years since the door (and full windows throughout) were installed.

 

[crank39]

Classic sign of wear in the gearbox yes, should be replaceable though relatively cheaply