The name is/was Grant-Lumley. I believe they were British.
I have a pair of M-100s. Bought them from Ray Lumley in 1984. Lumley and Grant were together first and produced the Grant Lumley amp. After the split Grant made the Grant amp and Ray produced the Lumley. Sweet tube sound.
They were in business until 1993 (I saw their ads until then). Since 1993 I have not seen any ads. Can I help you with anything regarding them?