Thanks for the Flataway tip! I've just been to Wiggle's site for a look. Presumably I'll need 2 of these (ie. not enough in 1 pack for 2 * 16" tyres)? I'm trying to imagine how they're actually inserted :-)
I needed two, but that was with 20" wheels. I can't remember if they are 305s or 349s on a Strida - if the former, you may be able to get away with 1 pack. They fit between the tube and tyre.
As regards the other points, if the Strida works for you and your wife over 10 miles +, then great. For me, it's too much of a compromise...