Brake caliper sound

[Rajsta]

My offside front caliper has developed a creaking sound. It's sounds metallic. Could this been the pad retaining springs? Seals?
I've made a video clip but unsure how to upload it

All calipers are oe from factory except this offside front which was replaced like for like 2 yrs ago

I've also noticed when driving over speed bumps the offside front sounds very crashy metallic like some things loose.

[swalker]

could be a few things, what is the pad thickness like?
see if you can reach in or see in the back. if the back is much thinner than the front you have a sticky caliper.
touch the wheel and see how warm it is - compare this to the other side.
it could also be a loose brake disc shield, reach in and see if this moves or rattles.
could be a retaining spring as you say - kick the wheel see if it rattles, then get someone to stand on the brake and kick it again.