Well, I can answer my own question a bit now, because Waterstone's had both! The difference is that the 5 Star is a bit more compact than the plain old Navigator at the expense of scale. The Navigator is 1.5 inch to the mile, the 5 Star 1.78 inch to the mile. Otherwise the detail and rrp is the same, and the Truckers Atlas is pretty much identical too. The Truckers Breakfast info seems to be in all variants, so maybe there's no great reason to pick that one.
They all have Bridge Numbers, with canals clearly shown. Locks are shown too, but I found a couple in places where locks are shown but there are none (Hanbury Junction). Still, it's bridge numbers that are handiest in my view, enabling you to switch from Nicholsons canal and a few hundred yards to full detail to see what's beyond or to plan pick up points for visitors, etc.
All three variants I found were 2014 editions, and all were spiral bound.
Thanks to all who contributed; I hope my input is also helpful to others. I'll be asking Santa for the Navigator rather than the 5 Star.
ETA an example about misplaced locks.