Well I've now copied the files from the Humax drive using HumaxRW and a live version of a 32-bit Linux Mint. I'll go into more details later about how.
And yes, I've saved them to my actual hard drive and not the live version folders!
My question for now though: is there any way of knowing whether they'll be playable after formatting the Humax drive and transferring them back, or is it just a case of needing to do that and hoping?!
They don't seem playable on the computer, so it would be good to check I've got all the right info and formats and there's nothing further that needs doing before formatting the Humax drive.
There were 3 programmes I was able to back up in normal mode, and the others I had to use the recovery mode to copy the files over, but the programme listings and information was there for almost all of them.