For wood carving, the smaller elbow adze blades seem to come in three profiles:
"straight" (as forginhill describes in post #7), "lip" which has a pronounced sweep or curve to the edge
and "gutter" which has upturned corners. The lip and gutter do a better job of cutting fiber when you
make a cross-grain strike.
My Kestrel Baby Sitka is a straight blade for shaping and texturing surfaces.
My Kestrel D-adze is also a straight blade for shaping.
If I did more hollows, big spoons and round-bottomed bowls, I'd have a lip adze blade in a minute.
The handles are not terribly difficult to prepare.
It is perhaps easiest to see those profiles here:
http://kestreltool.com/index.html
Over your way, Scandanavian bladesmiths such as Karlsson and John Neeman/Autine show fine examples.
There have got to be good bladesmiths in the UK who makes these, but I haven't kept track of them.
On your own, like many PacNW native carvers, the steel strips from truck/lorry leaf springs are the place to start.