Anne — Diamonds and squares subdivided by double intaglio lines are typical features of many Walsh patterns, as are also the long flake cuts, and were continued by the cutting team after their transfer to Tudor. However these features weren't exclusive in any way, and I've occasionally seen examples from other Stourbridge glassworks.
Note that Walsh table lamps were often only marked on the inside of the shade, leaving the base unmarked.
Could you bring it to Birmingham? I might be more informative if I could handle it.
Bernard C.