In that case it is the smaller of the two sizes made, the other being 7.5 inches tall. The guide price is twenty five quid, for what it is worth.
The price of the book on the secondary market is still

but it was twice that a while ago, perhaps it prompted a few extra copies to be offered for sale. It was 30 quid when new but now is out of print, which reinforces the point: buy them when they are published.....
At the time I wish I had forked out the 50 quid for his book on decanters, the asking is now

250

.
John