Hello all.
I visited a Maplin shop recently, and saw a wire stripper which I just had
to get.
It's made by Rolson, and costs £7.49.
Its working parts are made of cast steel, and are detachable (spares may not
be available, though).
It's automatic (no adjustment required), and works a treat.
It's well engineered, and is a welcome addition to my toolkit.

Sylvain.