The Vermio is a decent price as well.

http://www.erhaso.com/epages/Shop470...iefer195x70x20[1]

CF is always a little gamble, I've been in the quarry and had my hands on uncut stone. And there is a lot of variation of rock in a small area. Some is superfine others are slightly more coarse typical of all natural stone. If you can make sure the auction for CF has great pictures so you can gauge the surface. CF is also very common on Ebay.co.uk most of the time you will see 3-4 listed guaranteed rocks for a big price, then 3-4 stones that you can make an educated guess about.

UK stone terminology is strange. Unless you know what a hone is the common term would be "sharpening stone", "whetstone", "wet stone", or "oil stone". A private lister may not know to use the term hone as it is not a commonly used word in every day language. So search using many different descriptions. Also unless you know it's a CF a lister will probably list it as vintage, old, rare, or antique without specifying a stone type. If you want the bargains learn what they look like and take a cheap gamble 8inch stones are not uncommon, nor are stones with rough sides and uncut bottoms.