Ah, yes I was trying to import into my seedless wallet for testing. I have Electrum on another offline computer that has the seed.

If that is the reason it couldn't be imported then perhaps the error message could be improved to be a bit more helpful. At present there is no indication what the issue is.

If I do create the paper wallet then it would be nice to be able to watch the address from my seedless wallet, if only just to see that the coins are still there. Is that possible?

Yep, as noted in my post in the newbie forum I won't be putting any coins into that wallet 

Thanks flatfly.