Rosie told me she'd seen what looked like a water vole latrine down at White Lion Meadow, which is the main car park for the town, by Tesco: the place this blog was originally supposed to be about. If you recall, the voles disappeared from this particular stretch, I suspect because they were driven away by rats. Some might have been eaten, others moved upstream.
But these do look to me like water vole droppings, and if they are, that means we have at least one breeding female back on the site. It's very hard to see what's going on along the banks because of the tremendously lush vegetation (I'm not complaining, you understand!). I'll be keeping a close eye on the brook here from now on, though.