I think I am right in thinking that the Stevens & Williams' records are mostly lost, so probably no info on how long this was produced - style-wise I would say no more than 10 years, if that
Your rose bowl is pictured in Gulliver's Victorian decorative glass and is part of the Jewel range. A bubble of glass was machine threaded, cased in another layer and then blown into a 16-rib mould. Gulliver gives it a value of £35-45 in 2002, which seems to be toward the lower end of the items in his book, so who knows.