QNAP NAS Data Recovery

So i have a QNAP TS-453Be NAS which is running a RAID 5 configuration - 4 1TB disks with 3TB in total.

It looks like the Data has been deleted (but not overwritten) and all the data doesn't seem to be there in the file epxlorer. I want to run a dd image backup across the logical volume - is that possible for a RAIDed QNAP NAS? Or can i just DD each drive and somehow glue them together with some fancy software? Otherwise is there any native QNAP apps for something like this?

Can anyone point me in the correct direction? Any shred of information or experience would be greatly appreciated.