Head Unit Wrong Time + Replacement ?

Hi all,

I have recently bought a 1.2 2016 plate Yeti, however, the radio time just stays on 0:00 and occasionally fluctuates to just after 6 am in the morning, then back to 0:00 again. I am thinking the head unit has gone?

I am also looking to install a rear camera and if needed will replace the head unit as well, but what camera and head unit should i go for? Is it easy to install? Looking for one of those cameras that are built into the boot release rather than a camera i can fit anywhere on the vehicle!