Ok, this is my new working hypothesis

Produced by Richardson decorated by J Northwood.
I've been searching engravings etc of horses (Etruscan/classical etc) on various vases but not a stitch where I've looked at the engraving or pattern and though, yep, that looks like mine.
Then today I happened upon page 181 in Charles Hajdamach's British Glass 1800-1914.
The plate 160 shows '
Two templates used by the Northwood workshop about 1861-1862.Based on a photograph in John Northwood I
by John Northwood II.'
Both designs are very similar to mine but particularly the design on the right. No other horse design I've looked at has the same proportions, the movement of these/mine, the 'fine'ness of the horses etc. All others have thick legs or fat hoofs and most are quite 'static' in their depiction.
These templates are incredibly rare as they were thrown away.
These two templates can be matched to a frieze engraved on a jug which was a Richardson blank - it's shown on page 161 and here it is in the Broadfield House collection.
http://blackcountryhistory.org/collections/getrecord/DMUSE_ST430/The photography is rather unfortunate in that it's nearly impossible to see the engravings clearly. The templates are black on white background so much more easily comparable and I feel certain they are very close to my picture.
Hence new hypothesis of decoration by Northwood.
Very exciting find for me

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