Hello again Wesley,
I've just seen this first post and the images -- very useful.
I'd put this as having been made after Michael Harris left, so after 1972, for the following reasons:
- Although it appears a purpley colour, which can indicate a very early production, the browner tone suggests it's later.
- The 'wings' are squared off rather than being rounded, which is characteristic of Fish vases produced from the mid-1970s onwards.
- The signature is thickly applied using a vibropen, and is very large and swirly. Michael Harris' signature is smaller, tighter and more often than not executed with a diamond point tool, although some (still more thinly executed) vibropen signatures are known.
- the swirly signature here is currently believed to be that of Eric Dobson, Michael Harris' co-founder, and owner of the business after Michael left in 1972 until Joseph Said took over in 1985. This does not mean it was signed by Dobson himself (he was a businessman rather than a glassmaker or de facto designer), but it is likely. There are two primary variations of these swirly signatures - those that end with a vertical suggest Joseph Said, and those than end with a horizontal squiggle suggest Eric Dobson.
So, in all I would say mid to late 1970s - and a jolly lovely piece!
Hope this helps,