OK! I'll try that... thanks :)
In the meantime I've tried using mythtv which I already had installed, (I'd shut it down at startup so it didn't interfere with my testing), and am in the process of using that to see if it can both find and use the two devices.
Of course, I'dprefer to use tvh because mythtv is quite a load on my system, (which is not what one would call the most up to date of PC's... to put it mildly;)), which I also use for browsing and other stuff.
Anyway, I'll let you know :)
Of course, part of the exercise for me is to try and get things working and to provide help for others who may go through the same steps and have the same problem.
In fact what I MAY do, if I'm still struggling, is to use the TBS box on this system and try and use SAT_>IP connection to stream the data to me my raspberry pi3 which can also handle the RTL.
Anyway, we'll see.
Laters :)