My Scottish Glassmakers page on Scottish Glassmakers contains at least one sand-blasting engraver at Caithness, search on page (Alt +F3) for sand.
Should you come across any name/initial matches on Scottish Glass, please let me know for adding to this page.
Apart from engraving you can also get interesting graduated effects as in these Lindean Mill
I believe sand-blasting with sand is illegal in the UK now - but other material can be used. Does anyone know why and what?