I got a NextBase 322GW with the addition rear cam which directly links and powers from the main cam supplied and fitted from Halfords in the UK for £205.
You have to buy an additional SD to store your footage on, but get them pretty cheap, just make sure you order the right spec card.
But the NextBase app is good for viewing, saving and downloading the footage for both cams with ease without tappin away on the dash cam itself.
The main unit can also optionally display GPS Speedo which is nice to see rather than what's actually being recorded.