Late reply, but if you still need a response, I went for a cheap generic 4k resolution dashcam bought from Aliexpress, with both front and rear cameras. The quality is fine, with 4k front and 1080 rear.
The rear camera, on the right in the second pic is mounted through the bodywork and was a challenge to cable, but I managed to thread the cable around the roof lining and pillar trim, behind the glove box to the centre console, up behind the nearside rear storage box and rear trim, into the boot via the roll over hoop channel, ensuring the cable would not foul it's operation, behind the nearside boot lining and then, with the boot extended into it's high raised position (i.e. rear hinged for roof operating, then unlocked with the key stub and fully extended up) routed through the hinge channels along with the cabling for the boot latch and no. plate lights. A bit of a palaver, but with a long enough cable and a lot of patience I got there!
I did buy a hardwire kit for park mode, but didn't use it in the end, so have it just working off the ignition via a dual USB socket in the centre console which also powers a wireless phone holder/charger. The kit seemed straightforward to use by piggy backing on a permanent live fuse, which I would probably have found in the fuse box behind the drivers seat.
At the same time I wired in a reversing camera (the nearside camera mounted on a replacement no. plate light cover, also bought from Aliexpress. I think this upgrade is only possible if you have the NTG2.5 head unit used in the R230 facelift 2008 onward.
Hope this might help.
