Hadn't intended to show this plate, as the method/style of engraving is sufficiently different from m's original pieces........however, since Ming has now mentioned Jack Lloyd - and as this one does have some design features similar to Ming's - thought it worthwhile, especially as this piece is signed J. Lloyd - I've written "Stourbridge - Jack Lloyd c.1935" on the plate.
This is not Rock Crystal engraving, which is defined as possessing deep cutting, with polishing within the cuts etc., but am I correct in suggesting this might be a style of intaglio cutting called 'Polished Bright', which may have had its origins at Thomas Webb earlier in the C20?
Pieces shown earlier in this thread showed standard intaglio, i.e. areas within the cutting were very smooth (although not necessarily highly polished). On this plate, the engraved areas retain the lines made by the wheel, and which have then been highly polished, producing a sort of bright watery effect. The flowers have been left slightly matt. I can't see from the pix, whether any of Ming's pieces show polished grinding lines within the cutting, but the series of short dashes (middle piece) are certainly a common feature with my bowl.
This style of cutting appears to be very much in the minority, when compared to the overall volume of intaglio cut material - but it may not have been confined to Thomas Webb and Stourbridge Glass Co., only, although I don't know who else produced it.
However, none of this helps m - and it's possible we may not get an id for her piece due to the variety of producers of intaglio cut pieces
Ref. '20th Century British Glass' - Charles R. Hajdamach - Chapter Fourteen.