Dash cam fitting.

still looking for an slk/slc? Looking for SLK/SLC in your profile

based upon either r170 r171 or r172, you should have posted in the correct section

Yes, that is how mine is wired. Took a bit of fiddling about but basically camera is screen mounted on passenger side of rearview mirror. Cable across top of screen behind plastic trim and then down pillar, along the inside of the sill, behind carpet on rear bulkhead and then through the gap to the side of the boot under the roof hinge mechanism and behind the boot carpet/trim into the fuse box. All wiring is completely hidden. When working in the boot it is much easier if the separator is removed, that is held in place by four plastic nuts.
This is the camera:
380GW Dash Cam Bundle | Nextbase

EDIT - My camera is fitted with a battery for function with ignition off.

I powered my dash cam from the accessory power socket circuit in the centre console. Easy as I had to tap power as a part of android head unit install. Both bat and acc power available In this region.

A fuse box is located under the hood, on the driver's side, near the firewall. I used a fuse tap and the radio's fuse. Ran wire via top of the fender to door jam, then around the door jam, under the molding, to the side of the dash. Then, I ran up the A-pillar by simply pushing behind the trim and across the window, pushing under the trim and around the center console to the passenger side of the car, behind the mirror, and plugged the camera in. This is a simple way and does not require running wire from the trunk all the way to the camera.

I used the radio fuse so that when the car's switch is off, the power to the camera is also off. This way, you avoid battery drain.

Both helpful and thank you for taking the time to respond, I have wired into the fuse box in the boot/trunk just under and behind where the roof stores, I could only find two fuses that were powered by the ignition being energised. The biggest issue was routing the cable which I routed through the hole behind the passengers seat belt, the only issue is keeping the wiring clear of the roof hinging system. Having said all that everything went well. But thanks again for all input into the matter.

I just wired mine into the radio feed. Easy to find, no faffing about.

I know this is quite an old topic but I have just fitted a Viofo A119Mini 2 to our SLC. As others have said, I fixed the camera to the windscreen to the left of the mirror and removed the A pillar trim and cill to run the wires to the back of the cockpit under the carpet. At the back, I thought about running the wires through the hole by the seat belt mount but didn't like the possibility of the cables catching the belt of the roof hinge. On the back bulkhead (RHD car) there is a large , black metal plate attached to the bulkhead by 10 hex head bolts and 1 torx bolt (which bolts the belt reel to the plate). I removed this plate and saw 2 bundles of cables coning up from the floor and heading towards the boot. I took a length of 1mm2 2 core & earth cable and gently pushed it between the 2 bundles of cables and found that it came out in the boot right next to the earting post on the LHS (I had removed the boot separator and the carpet covering the SAM). I used this cable to pull the camera cables through
The hard-wire kit had a small plastic control box to set the switch-off voltage for the camera to save battery drain and I used sticky back velcro to attach this to a small recess in the cockpit bulkhead so that the carpet could cover it without a bulge. I had to extend the 3 wires by about 30-40cm to get to the SAM and then I used fuse 57 (live) and 56 (switched). These needed special fuse holders from MB to lock into the SAM (part Nos MA004 545 62 01 & MA004 545 58 01 plus the spring contacts to solder onto the wires (MA004 545 52 26). These each cost about £5 each from MB and I used a 1A standard fuse in each. The earth wire was tagged to a suitable earth point near the SAM.
I'm sorry this is a bit long winded but I thought it might help anyone contemplating fitting a dash cam. Our car is a 2017 SLC but I would imagine that all R172 models are the same or very similar but if you go this route, please check that these 2 SAM fuses are live and switched in your car just in case MB have made changes in different years.