Production of Nailsea glass did not continue after 1874, but the works were leased from the owners from about 1855:
From 1855, the works were leased to Samuel Bowen. ... he was bought out by James Hartley ... he later sold the works to Chance Brothers.
Chance Expressions, p.4
It is also worth noting that Nailsea was not in the main a producer of fancy items and friggers, but its core business was producing sheet glass (window glass). I have a lot more to include in Chance Reflections
whenever that is published!
I'm no expert on Nailsea, and my 'expertise' is seriously limited as all my books on the subject are currently packed away (Margaret Thomas' book on the history of the works is one such), but it would be difficult to attribute this as Nailsea without a little more proof, as M and JP point out.