Thanks Jim, for the reply. The trouble is, if you haven't been formally taught these rules, the more subtle ones are not so easy to pick up.

Dicho, you say:
"Crazy Eddie, your sentence with the semicolon makes me pause fractionally; if you placed a comma there, the tendency is to race on and perhaps lose some of the meaning."
Surely the comma should make you pause; if I wanted you to race on, I wouldn't have used a punctuation mark!

Is it a question of degree in a case like this?

(I've used a semicolon above. I could have used a full-stop, (or a query) but I think the semicolon makes the connection between the clauses clearer. Is this usage correct?