As Alex has mentioned sounds like you’ve got a few issues here which could be different symptoms,
* unfortunately it’s fairly common that some garages clean the carriers too aggressively and take away the carrier material itself allowing the pads to move too freely in the carriers - also another point, does it have the shims installed correctly? sometimes when they’re missing or thrown away you get that click noise.
* the squeaky bed sound as Alex suggested seems to be possible mot related to the handbrake shoes, I would have thought that the garage would have adjusted these when replacing discs and pads. However sometimes the shoes wear unevenly and can sometimes interfere with the mating surface, another thing to note is if the shoes are catching there’s only the two spring retainers holding the shoes in which could be your creaky noise id suggest removing the discs and assessing the state of the shoes and adjustment to rule out of the equation.
when you are low speed braking, have you used the handbrake slowly to see if the noise stops or becomes worse?
we’ve had it before where someone takes the old discs off without de adjusting the handbrake pulls the spring retainer through the crusty backing plate and then the spring then goes into the hamster wheel also making an annoying terrible noise?