Of course, it might not be Nazeing but looks to have the right colour and bubbles, so will go with that provenance for the time being.
The colour is one of the 'greens' - possibly a little too turquoise for Sherwood - and certainly at the extreme end of green. The slightly rough scar under the base, plus the bubble structure and colour are good candidates for Nazeing - but it's the shape, produced I assume on a slump mould that makes it unusual.
Nowhere in the Nazeing book can I find anything of a shape that would suggest the factory were using this method for shaping bowls, and apart from some ashtrays, there is nothing that I can see other than circular rims.
Diameter is a tad under 6 inches (c. 150 mm).
So, a bit confused - is this a trial piece or did Nazeing use slump moulds and it's just a case that nothing managed to get into the book - or simply nothing to do with Nazeing?? Age wise I'd have thought somewhere around 1950 - 60.
All thoughts welcome and thanks for looking
Ref. '75 years of diverse Glass-making to the World - A celebration of Nazeing Glass Works 1928 - 2003 - Geoffrey C. Timberlake - 2003.