Thank you for showing this unusual piece, Roy. It is certainly the first example that I’ve ever seen.
I can see why you thought it might be by Greener at first – the pieces from their RD 160244 of 3 November 1890 have similar ‘bobbles’, and many of the pieces are seen in blue opalescent glass.
Neil Harris has a description, but no photo, of the fairy light at
https://sites.google.com/site/molwebbhistory/Home/registered-designs/burtles-tate-designs-by-date/burtles-tate-1886-1889
“1 OCTOBER 1888
Design Number
109531
Description
Fairy light
A semi-circular piece, the glass is patterned with repeating circular holes”
except that what presumably appear to be holes on the design representation are actually domed protruberences.
Also referenced at
http://www.fairy-lamp.com/Fairylamp/FairyLampDesignNumbers_All.html
as Ruf – 110, but again, no photo.
Fred.