I was told the same about the chews - not to give them till they're 14+ weeks old, and supervise them when they've got one "just in case" - as with all bones (fake or natural).
On insurance - I've just gone with M&S too. It's got the highest levels of cover to match the other most comprehensive insurers but is much cheaper - I was quoted over £220 p.a. with PetPlan, but £163 with M&S - and a lower excess too. At the moment, there's a 10% discount if you buy online.
Sorry - can't remember from your earlier post if Pringle (who is gorgeous, by the way!) came from a Kennel Club registered breeder? If so - you've got six weeks' free insurance through the Kennel Club scheme (or you should have!), running from the date you collected her. You could buy the M&S insurance now, to start with effect from the end of that six week period. If not - just make sure you diarise when that six weeks runs out!
Denise