Are they still going or have they gone bump?
My Butters says ButtersUK on the side. Made in Telford. Had a minor prob with the feed motor last month. Took it to the agent, it got fixed with new motor runs sweeeet again. I dunno if there is an association, but I was told when I bought it that Butters had been bought out and were now making these. Mine looks very different to the orange sets that I'd associate with AMT, but it does clearly say Butters on the side. It's a Weld Wizard - and I love it.
Anymore than that and I shall have to start making things up.
FF