That's me added an internal hard disk to the Octagon now. Screws and connection cables were supplied with the receiver as well as an external data cable for the 2 back usb ports. Recording is working. Still to try is to record a 4.2.2 channel and play with Nvidia Shield TV box. Got to find the feed first with the Dr HD blind search, then input the details into the Octagon and hope it has not disappeared before I hit the record button!
The satellite search screen really needs a signal indicator. I miss that badly. It also needs a transponder delete button. Is all very well downloading a ready made transponder list but when it covers the different footprints a satellite covers it means the satellite search has to check a lot of transponders with no signal slowing down the search process.
Using a couple of external satellite editors and sending the amended details back the receiver was unsuccessful and ended up with a non working channel list. Backing up your settings is soooo important! Editing Satellites.xml and then rebooting the receiver worked.
I'm learning, but patience, I am finding, is absolutely essential with this kind of receiver.