For want of a ha'porth of nails
Thanks for all the suggestions and offers of glue but my new(ish) boots have gone to the boot doctor after the (many-inch) heel fell off last night. It turns out that (as suspected) the original construction was rather sloppy - there were insufficient staples holding the heel to the body of the shoe and the few used were poorly sited. On the other hand, I probably shouldn't have put them through the stresses of running when they're (obviously) not designed to handle it. The nice Covered Market shoe people are sending both off for pneumatic stapling and have thrown in replacement of the heel rubbers. Not cheap but I'll be getting back better quality footwear for a lot less than the cost of replacing the shoes. (Internet bargains on ebay or elsewhere are all very well, if you can find the right thing in the right size at the right price and the right time, but fashion-constructed so no more likely to hold together and I know this pair fit the way I want).
Very bitter cachous
Children are good at swallowing small things - its surprising (though shouldn't be) how important it is to
make sure they don't swallow these. Failing that, its critical to identify as early as possible if there's any chance they have done so - that's the main problem in mitigating the consequences. (Cases mostly are more attributable to a child's ingenious curiosity rather than parental carelessness: In 60 percent of the cases involving children under age 6, the child has removed the battery from the electronic device.).