Anyway, I'm now back on line, which let me check the Sumvision Cyclone Live media player I bought. It does work, and I got e.g. a lot of NASA stuff, but unfortunately doesn't support the two services I particularly want - YouTube and BBC iPlayer.
YouTube is there but videos don't play; really not sure why, has the format changed in the last few months. No British sources are there at all, especially not iPlayer.
So I've asked for a refund, and it's back to the drawing board. Meanwhile Morgans are out of stock of the Intempo Evolve, which was the first thing I looked at, and I gather that Apple TV also fails to support most British services. Any other suggestions?