I'll go along with what you say Mark, but nothing was ever proved conclusively as the killer. Except that lead shot was found and we were holding a smoking gun (so to speak).
I saw a bit on the news about Chesil Beach. Apparently, there's no more stones being washed up there, so they're stopping people from removing what's left. About time.
As for the shot, it's zinc down to size 6 and lead below that as zinc can't be made so pliable is the smallest sizes (source - Nigel May, Dinsmores). You're right about the 4s and 6s, zinc aren't as small for the same weight. You can see that by comparing a 6 with an 8 which is about half the size, yet the weight is 80% that of the 6.
I do appreciate the new weights even though they are 5 times more expensive. At least I have got rid of the attitude of 'use it and chuck it' (it used to go in my wast bag, not in the river btw).
... and I love swans!