QVIS 4CHN-Lite DVR

Hi, wondering if anyone can help me out. My father has a QVIS 4 camera CCTV system installed in his home - he updated the passwords for security reasons (grandkids) and due to the infrequency of using the DVR for playback has totally forgotten the updated password for the admin account. Is there anyway of performing a factory reset to return the DVR to 'out of box' and default passwords so that I can recover the system and then reconfigure the whole setup for him?

I've tried all the usual passwords he thought he'd have used and I've also tried the defaults such as 888888 / 666666 / 000000 / 123456 etc to no avail. I'm locked out after 3 failed attempts for 30mins at a time.

Hopefully someone can point me in the right direction as the original installer wants nothing to do with it

It looks like this without the HDMI logo:

https://www.amazon.co.uk/Qvis-Atlantis-Channel-H-264-Mobile/dp/B00MEDBXZC

Thanks!