During the years 1964 and 1965 I certainly never heard the term "dingle"
used concerning weather of any type, so it must have appeared after that.
Odd, the way in which some terms appear, some disappear, some persist,
and some change. Ken Lax, in his list of Halley Bay slang, comments on
the meanings of "spon". In 1964-5 it was not widely used but I
certainly heard it from time to time with the meaning of "good" or
"excellent". I have no idea where this originated. We also knew the
phrase "I've been sponned!", but that was quite separate.
For what it is worth, the 1994 edition of the Dictionary of Contemporary
Slang by Tony Thorne gives two meanings for "spon", both different. One
is short for "spondulicks" (money), and the other (described as a childish
term of abuse, obsolete since the early 1960s) is "a fool".
[19 March 2007]