Thanks for this Pwayne, I agree with you that attributions for some of these unsigned pieces is tricky to say the least.
I have left the attribution fairly vague, with suggestions as to who it might be made by, and will leave it to the collector to decide if they like the look of the bowl regardless of maker.
And yes, I think often Millers prices can be divided by 5 to reach a reasonable sum

Although in other cases, they have estimated low, and I have found that item can reach a much much higher sum. So they are, in common with most price guides, a source of information (although it would seem that is just as flakey at times) rather than value.