Thanks much for that reply, Alan, and sorry about the late reply as my internet was down yesterday.
Mr. Manson Snr also confirmed your description about the weight. In addition, he said that:
"Yes I can confirm that this weight is a Paul Ysart Harland weight, I can also confirm that the lampwork and the weight were both made by Paul Ysart. David Hurry and myself both worked at Harland in the nineteen seventies but I can tell by the shape of the lampwork fish that it was made by Paul, he always made his sandfish as he called them shorter and fatter if that's a proper description."
He also noted the amusing price inflation, of course:
"Out of interest the 0riginal price of that particular weight was £12.00..."
Ha! Talking about irrational exuberance.