The first thing I look for when I’m after Barbel is a place with either a nice gravel bed or Rocky bed, or even an area with nice clean sand on its bed; which preferably has some flow in it, and cabbages and streamer weed makes it even more likely for it to hold Barbel.
As an example the river Lea goes through areas of thick silt where almost no Barbel are caught at all but it also has stretches of river with hard gravelly bottoms and lots of streamer weed and it’s these stretches which are often populated with quite a lot of Barbel. I won’t name any of these places for obvious reasons.
I do however know of a silty backwater where some nice Barbel can often be found although the Barbel can swim into this silty backwater from a clean gravel bottomed stream which makes it ideal.
Features to look out for are the outsides of bends in the river which have often been scoured out during floods, or just downstream of them; Places with deep undercut banks and bank cutouts next to tree roots etc., places that are lined with a lot of rush beds which also have a steady flow running past them over gravel, large beds of streamer weed and cabbages and with lots of different depths. I often find Barbel above cattle drinks just before the water starts to shallow up slightly.
If you can find an older type of Weir then fishing right under the white water along its sill will often find some Barbel who are lying in the slightly calmer water below the white water above, often in undercuts that have been bored out over the years by the scouring of the water coming over the weir sill.
The tail end of some of these Weirs often produce a few Barbel too.
Of course the list goes on and on, but I hope this has been of some use to you Paul.
Keith