this type of decoration and colour combination - plain green trailing producing a single spiral, plus the crimped rim - does have a precedent. Mervyn Gulliver includes a couple of pieces that appear to have similar features, and for which he gives dates in the last 20 years of the C19, although he doesn't venture to suggest a maker. Have no idea as to the cause of the orange effect.
My own opinion is to say not Stuart, but in truth I'm really not sure, although in any event I think it highly unlikely that a maker would ever be found, and dating is equally difficult.
Ref. 'Victorian Decorative Glass British Designs, 1850 - 1914' - Mervyn Gulliver - 2002. pp. 194 & 200.