What a very comprehensive contribution from IO540 (Mr Lycoming?). Thanks a lot.
Your last paragraph first - "None of the above options . . . do away with the need to buy the printed charts . . ." - too right, though not all the advertising material for software emphasises this basic airmanship point strongly.
My foreign flying was done when the Queen was paying, so now that I'm an OAP most of my destinations are likely to be in the UK. That being so, I'm going to take your suggestion and try out SkyDemon Lite for a while to see how it goes.
Speaking of OAPs, is your age quoted here correct? If so, kudos - are you also bold, by any chance?