my thanks also to Stephen for his very useful information.
The following maybe removed if it's considered out of place here, but found this small blue, clear handled, posy vase this morning and thought a pic or two - especially showing what appears to be a snapped pontil - might be of interest.
Geoff. Timberlake comments in his book ('A Celebration of Nazeing Glass Works 1928 - 2003' - page 57), that - "This does not work as well as a design which may explain why so few examples of this style are known"
This posy bowl is seen quite commonly at boot fairs etc., but without the handles, usually, and must admit this is the first I've found with handles.
Presumably this smallish snapped rough pontil scar remained unpolished in view of the slightly concave base - which avoids any scratching of surfaces etc. - and saved spending additional time on an otherwise low value item.
Does this date to the 1950's or is it later?