Did you not read the previous posts in this thread? If they were recorded in HD, unless you had nowster's patch when they were recorded, forget it. They are still encrypted. Nowster's patch decrypts them on the fly while they are recording by means of some magic potion. They will only play back on the Foxsat on which they were recorded.
No decryption on the fly is required. All BBC programmes (satellite and freeview) are transmitted without any sort of encryption. Any generic DVB-T2/DVB-S2 receiver with recording capability is capable of recording the original non-encrypted data stream as is.
Licenced Freeeview+ and Freesat+ boxes are forced to provide a broadcaster with the capability to provide data flags that force the box to :
1 Encrypt HD on copying to the Hard Disk using a unique key to the box. (Often believed to be based on the box serial number and MAC address).
2 Apply a restriction on the number of digital copies that can be made to an external device,
For instance on a Foxsat-HDR the BBC usually specify a copy once limit. You can copy an encrypted HD file to a USB device once and then replay it from USB provided you use the box that recorded the content in the first place. This is easily fixed with the custom firmware because this behaviour is controlled by a simple flag in the .hmt sidecar file.
There is a major difference how the broadly comtemporary HDR FOX T2 (and derivatives) treat encryption compared to the Foxsat-HDR.
The HDR FOX T2 encrpyts all recorded content (HD and SD). Because it is capable of decrypting SD on copying to USB (which makes transfers very slow). The decrypt on copy capability is controlled by a easily patched flag in the .hmt file. This basically allows existing HD encrypted content to be decrypted after recording.
The Foxsat-HDR has no such capability, once the box has decrypted the content to a recording, you cannot decrypt it.
Nowsters patch is just a very small patch to the Humax settop app which basically causes the box to ignore the broadcaster encrypt on recording flag.
The time shift buffer file on a Foxsat-HDR is buffered without encryption and recordings made using non-freesat mode are also not encrypted. It has alway been possible even pre the CF, to manually record HD free of encryption using non-freesat mode.