Graham,
Gee it's been a few years but as I remember, the formulas in his book, which are rather complicated with numerous correction factors, yielded a cg location far too rearward for a canard I was building.
It crashed immediately upon takeoff. Next time I used someone else's formulas and had success (after two months of rebuilding!).
I can't remember whether the problem was with the neutral point calculation or the suggested static margin. I seem to remember that the effect of the foreplane was discounted by an upwash factor and this resulted in the np problem. The other issue was the fact that the same formula (with a sign correction) was used for both regular tail-last planes and canards.
I do remember being rather p----- about it though.
Allan